diff --git a/OpenRA.Game/Download.cs b/OpenRA.Game/Download.cs
index 4cd997ae7d..30eb18384a 100644
--- a/OpenRA.Game/Download.cs
+++ b/OpenRA.Game/Download.cs
@@ -70,6 +70,7 @@ namespace OpenRA
 		{
 			Game.OnQuit -= Cancel;
 			wc.CancelAsync();
+			wc.Dispose();
 			cancelled = true;
 		}
 	}
diff --git a/OpenRA.Game/FileSystem/MixFile.cs b/OpenRA.Game/FileSystem/MixFile.cs
index f28d17b2b9..e4739c99c2 100644
--- a/OpenRA.Game/FileSystem/MixFile.cs
+++ b/OpenRA.Game/FileSystem/MixFile.cs
@@ -17,7 +17,7 @@ using OpenRA.FileFormats;
 
 namespace OpenRA.FileSystem
 {
-	public class MixFile : IFolder
+	public sealed class MixFile : IFolder, IDisposable
 	{
 		readonly Dictionary<uint, PackageEntry> index;
 		readonly long dataStart;
@@ -258,5 +258,11 @@ namespace OpenRA.FileSystem
 					s.Write(file.Value);
 			}
 		}
+
+		public void Dispose()
+		{
+			if (s != null)
+				s.Dispose();
+		}
 	}
 }
diff --git a/OpenRA.Game/FileSystem/ZipFile.cs b/OpenRA.Game/FileSystem/ZipFile.cs
index c7705a0949..99e87014b9 100644
--- a/OpenRA.Game/FileSystem/ZipFile.cs
+++ b/OpenRA.Game/FileSystem/ZipFile.cs
@@ -8,6 +8,7 @@
  */
 #endregion
 
+using System;
 using System.Collections.Generic;
 using System.IO;
 using System.Text;
@@ -16,7 +17,7 @@ using SZipFile = ICSharpCode.SharpZipLib.Zip.ZipFile;
 
 namespace OpenRA.FileSystem
 {
-	public class ZipFile : IFolder
+	public sealed class ZipFile : IFolder, IDisposable
 	{
 		string filename;
 		SZipFile pkg;
@@ -105,6 +106,12 @@ namespace OpenRA.FileSystem
 			pkg.Close();
 			pkg = new SZipFile(new MemoryStream(File.ReadAllBytes(filename)));
 		}
+
+		public void Dispose()
+		{
+			if (pkg != null)
+				pkg.Close();
+		}
 	}
 
 	class StaticMemoryDataSource : IStaticDataSource
diff --git a/OpenRA.Game/Game.cs b/OpenRA.Game/Game.cs
index 93f081562d..6e12cd9827 100644
--- a/OpenRA.Game/Game.cs
+++ b/OpenRA.Game/Game.cs
@@ -504,6 +504,8 @@ namespace OpenRA
 			// Ensure that the active replay is properly saved
 			if (orderManager != null)
 				orderManager.Dispose();
+				
+			Renderer.Device.Dispose();
 
 			OnQuit();
 		}
diff --git a/OpenRA.Game/GameRules/MusicInfo.cs b/OpenRA.Game/GameRules/MusicInfo.cs
index 59fca18bb1..983b0786d3 100644
--- a/OpenRA.Game/GameRules/MusicInfo.cs
+++ b/OpenRA.Game/GameRules/MusicInfo.cs
@@ -31,7 +31,8 @@ namespace OpenRA.GameRules
 				return;
 
 			Exists = true;
-			Length = (int)AudLoader.SoundLength(GlobalFileSystem.Open(Filename));
+			using (var s = GlobalFileSystem.Open(Filename))
+				Length = (int)AudLoader.SoundLength(s);
 		}
 
 		public void Reload()
@@ -40,7 +41,8 @@ namespace OpenRA.GameRules
 				return;
 
 			Exists = true;
-			Length = (int)AudLoader.SoundLength(GlobalFileSystem.Open(Filename));
+			using (var s = GlobalFileSystem.Open(Filename))
+				Length = (int)AudLoader.SoundLength(s);
 		}
 	}
 }
diff --git a/OpenRA.Game/Graphics/Sheet.cs b/OpenRA.Game/Graphics/Sheet.cs
index 3c8eb4f078..1467c183e6 100644
--- a/OpenRA.Game/Graphics/Sheet.cs
+++ b/OpenRA.Game/Graphics/Sheet.cs
@@ -40,31 +40,34 @@ namespace OpenRA.Graphics
 
 		public Sheet(string filename)
 		{
-			var bitmap = (Bitmap)Image.FromStream(GlobalFileSystem.Open(filename));
-			Size = bitmap.Size;
-
-			data = new byte[4*Size.Width*Size.Height];
-			var b = bitmap.LockBits(bitmap.Bounds(),
-				ImageLockMode.ReadOnly, PixelFormat.Format32bppArgb);
-
-			unsafe
+			using (var stream = GlobalFileSystem.Open(filename))
+			using (var bitmap = (Bitmap)Image.FromStream(stream))
 			{
-				int* c = (int*)b.Scan0;
+				Size = bitmap.Size;
 
-				for (var x = 0; x < Size.Width; x++)
-					for (var y = 0; y < Size.Height; y++)
+				data = new byte[4 * Size.Width * Size.Height];
+				var b = bitmap.LockBits(bitmap.Bounds(),
+					ImageLockMode.ReadOnly, PixelFormat.Format32bppArgb);
+
+				unsafe
 				{
-					var i = 4*Size.Width*y + 4*x;
+					int* c = (int*)b.Scan0;
 
-					// Convert argb to bgra
-					var argb = *(c + (y * b.Stride >> 2) + x);
-					data[i++] = (byte)(argb >> 0);
-					data[i++] = (byte)(argb >> 8);
-					data[i++] = (byte)(argb >> 16);
-					data[i++] = (byte)(argb >> 24);
+					for (var x = 0; x < Size.Width; x++)
+						for (var y = 0; y < Size.Height; y++)
+						{
+							var i = 4 * Size.Width * y + 4 * x;
+
+							// Convert argb to bgra
+							var argb = *(c + (y * b.Stride >> 2) + x);
+							data[i++] = (byte)(argb >> 0);
+							data[i++] = (byte)(argb >> 8);
+							data[i++] = (byte)(argb >> 16);
+							data[i++] = (byte)(argb >> 24);
+						}
 				}
+				bitmap.UnlockBits(b);
 			}
-			bitmap.UnlockBits(b);
 		}
 
 		public ITexture Texture
diff --git a/OpenRA.Game/Graphics/SpriteFont.cs b/OpenRA.Game/Graphics/SpriteFont.cs
index a37c2d21f3..d8754e2ccf 100644
--- a/OpenRA.Game/Graphics/SpriteFont.cs
+++ b/OpenRA.Game/Graphics/SpriteFont.cs
@@ -108,27 +108,29 @@ namespace OpenRA.Graphics
 				Offset = { X = face.Glyph.BitmapLeft, Y = -face.Glyph.BitmapTop }
 			};
 
-			unsafe
-			{
-				var p = (byte*)face.Glyph.Bitmap.Buffer;
-				var dest = s.sheet.Data;
-				var destStride = s.sheet.Size.Width * 4;
-
-				for (var j = 0; j < s.size.Y; j++)
+			// A new bitmap is generated each time this property is accessed, so we do need to dispose it.
+			using (var bitmap = face.Glyph.Bitmap)
+				unsafe
 				{
-					for (var i = 0; i < s.size.X; i++)
-						if (p[i] != 0)
-						{
-							var q = destStride * (j + s.bounds.Top) + 4 * (i + s.bounds.Left);
-							dest[q] = c.Second.B;
-							dest[q + 1] = c.Second.G;
-							dest[q + 2] = c.Second.R;
-							dest[q + 3] = p[i];
-						}
+					var p = (byte*)bitmap.Buffer;
+					var dest = s.sheet.Data;
+					var destStride = s.sheet.Size.Width * 4;
 
-					p += face.Glyph.Bitmap.Pitch;
+					for (var j = 0; j < s.size.Y; j++)
+					{
+						for (var i = 0; i < s.size.X; i++)
+							if (p[i] != 0)
+							{
+								var q = destStride * (j + s.bounds.Top) + 4 * (i + s.bounds.Left);
+								dest[q] = c.Second.B;
+								dest[q + 1] = c.Second.G;
+								dest[q + 2] = c.Second.R;
+								dest[q + 3] = p[i];
+							}
+
+						p += bitmap.Pitch;
+					}
 				}
-			}
 			s.sheet.CommitData();
 
 			return g;
diff --git a/OpenRA.Game/Graphics/SpriteLoader.cs b/OpenRA.Game/Graphics/SpriteLoader.cs
index d197bc7cc0..67d2571b99 100644
--- a/OpenRA.Game/Graphics/SpriteLoader.cs
+++ b/OpenRA.Game/Graphics/SpriteLoader.cs
@@ -33,10 +33,10 @@ namespace OpenRA.Graphics
 
 		Sprite[] CacheSpriteFrames(string filename)
 		{
-			var stream = GlobalFileSystem.OpenWithExts(filename, exts);
-			return SpriteSource.LoadSpriteSource(stream, filename).Frames
-				.Select(a => SheetBuilder.Add(a))
-				.ToArray();
+			using (var stream = GlobalFileSystem.OpenWithExts(filename, exts))
+				return SpriteSource.LoadSpriteSource(stream, filename).Frames
+					.Select(a => SheetBuilder.Add(a))
+					.ToArray();
 		}
 
 		public Sprite[] LoadAllSprites(string filename) { return sprites[filename]; }
diff --git a/OpenRA.Game/Graphics/VoxelLoader.cs b/OpenRA.Game/Graphics/VoxelLoader.cs
index 0846d6b8ab..6bd96377f8 100644
--- a/OpenRA.Game/Graphics/VoxelLoader.cs
+++ b/OpenRA.Game/Graphics/VoxelLoader.cs
@@ -210,8 +210,12 @@ namespace OpenRA.Graphics
 
 		Voxel LoadFile(Pair<string,string> files)
 		{
-			var vxl = new VxlReader(GlobalFileSystem.OpenWithExts(files.First, ".vxl"));
-			var hva = new HvaReader(GlobalFileSystem.OpenWithExts(files.Second, ".hva"));
+			VxlReader vxl;
+			HvaReader hva;
+			using (var s = GlobalFileSystem.OpenWithExts(files.First, ".vxl"))
+				vxl = new VxlReader(s);
+			using (var s = GlobalFileSystem.OpenWithExts(files.Second, ".hva"))
+				hva = new HvaReader(s);
 			return new Voxel(this, vxl, hva);
 		}
 
diff --git a/OpenRA.Game/IGraphicsDevice.cs b/OpenRA.Game/IGraphicsDevice.cs
index aa6ced58ab..01c24b8e8f 100755
--- a/OpenRA.Game/IGraphicsDevice.cs
+++ b/OpenRA.Game/IGraphicsDevice.cs
@@ -34,7 +34,7 @@ namespace OpenRA
 
 	public enum BlendMode { None, Alpha, Additive, Subtractive, Multiply }
 
-	public interface IGraphicsDevice
+	public interface IGraphicsDevice : IDisposable
 	{
 		IVertexBuffer<Vertex> CreateVertexBuffer(int length);
 		ITexture CreateTexture(Bitmap bitmap);
@@ -58,8 +58,6 @@ namespace OpenRA
 		void DisableDepthBuffer();
 
 		void SetBlendMode(BlendMode mode);
-
-		void Quit();
 	}
 
 	public interface IVertexBuffer<T>
diff --git a/OpenRA.Game/InstallUtils.cs b/OpenRA.Game/InstallUtils.cs
index 5e098e54f3..07e75afa10 100644
--- a/OpenRA.Game/InstallUtils.cs
+++ b/OpenRA.Game/InstallUtils.cs
@@ -93,8 +93,9 @@ namespace OpenRA
 			List<string> extracted = new List<string>();
 			try
 			{
-				var z = new ZipInputStream(File.OpenRead(zipFile));
-				z.ExtractZip(dest, extracted, s => onProgress("Extracting " + s));
+				using (var stream = File.OpenRead(zipFile))
+				using (var z = new ZipInputStream(stream))
+					z.ExtractZip(dest, extracted, s => onProgress("Extracting " + s));
 			}
 			catch (SharpZipBaseException)
 			{
diff --git a/OpenRA.Game/MiniYaml.cs b/OpenRA.Game/MiniYaml.cs
index 7b7274dd46..67f94ae51a 100755
--- a/OpenRA.Game/MiniYaml.cs
+++ b/OpenRA.Game/MiniYaml.cs
@@ -172,13 +172,11 @@ namespace OpenRA
 
 		public static List<MiniYamlNode> FromFileInPackage(string path)
 		{
-			StreamReader reader = new StreamReader(GlobalFileSystem.Open(path));
 			List<string> lines = new List<string>();
-
-			while (!reader.EndOfStream)
-				lines.Add(reader.ReadLine());
-			reader.Close();
-
+			using (var stream = GlobalFileSystem.Open(path))
+			using (var reader = new StreamReader(stream))
+				while (!reader.EndOfStream)
+					lines.Add(reader.ReadLine());
 			return FromLines(lines.ToArray(), path);
 		}
 
diff --git a/OpenRA.Game/Network/Connection.cs b/OpenRA.Game/Network/Connection.cs
index 8c0d964c14..e2a118ffd5 100755
--- a/OpenRA.Game/Network/Connection.cs
+++ b/OpenRA.Game/Network/Connection.cs
@@ -86,7 +86,7 @@ namespace OpenRA.Network
 			if (packet.Length == 0)
 				throw new NotImplementedException();
 			lock (this)
-				receivedPackets.Add(new ReceivedPacket { FromClient = LocalClientId, Data = packet } );
+				receivedPackets.Add(new ReceivedPacket { FromClient = LocalClientId, Data = packet });
 		}
 
 		public virtual void Receive(Action<int, byte[]> packetFn)
@@ -102,10 +102,16 @@ namespace OpenRA.Network
 				packetFn(p.FromClient, p.Data);
 		}
 
-		public virtual void Dispose() { }
+		protected virtual void Dispose(bool disposing) { }
+
+		public void Dispose()
+		{
+			Dispose(true);
+			GC.SuppressFinalize(this);
+		}
 	}
 
-	class NetworkConnection : EchoConnection
+	sealed class NetworkConnection : EchoConnection
 	{
 		TcpClient socket;
 		int clientId;
@@ -193,22 +199,27 @@ namespace OpenRA.Network
 
 		bool disposed = false;
 
-		public override void Dispose()
+		protected override void Dispose(bool disposing)
 		{
-			if (disposed) return;
+			if (disposed)
+				return;
 			disposed = true;
-			GC.SuppressFinalize(this);
 
 			t.Abort();
-			if (socket != null)
-				socket.Client.Close();
+			if (disposing)
+				if (socket != null)
+					socket.Client.Close();
 			using (new PerfSample("Thread.Join"))
 			{
 				if (!t.Join(1000))
 					return;
 			}
+			base.Dispose(disposing);
 		}
 
-		~NetworkConnection() { Dispose(); }
+		~NetworkConnection()
+		{
+			Dispose(false);
+		}
 	}
 }
diff --git a/OpenRA.Game/Network/OrderManager.cs b/OpenRA.Game/Network/OrderManager.cs
index 12fd17d286..5be8f59730 100755
--- a/OpenRA.Game/Network/OrderManager.cs
+++ b/OpenRA.Game/Network/OrderManager.cs
@@ -15,7 +15,7 @@ using OpenRA.Primitives;
 
 namespace OpenRA.Network
 {
-	public class OrderManager : IDisposable
+	public sealed class OrderManager : IDisposable
 	{
 		readonly SyncReport syncReport;
 		readonly FrameData frameData = new FrameData();
@@ -197,22 +197,10 @@ namespace OpenRA.Network
 			++NetFrameNumber;
 		}
 
-		bool disposed;
-		protected void Dispose(bool disposing)
-		{
-			if (disposed)
-				return;
-
-			if (disposing)
-				Connection.Dispose();
-
-			disposed = true;
-		}
-
 		public void Dispose()
 		{
-			Dispose(true);
-			GC.SuppressFinalize(this);
+			if (Connection != null)
+				Connection.Dispose();
 		}
 	}
 }
diff --git a/OpenRA.Game/Network/ReplayConnection.cs b/OpenRA.Game/Network/ReplayConnection.cs
index 275d3003d7..32afbfad6a 100755
--- a/OpenRA.Game/Network/ReplayConnection.cs
+++ b/OpenRA.Game/Network/ReplayConnection.cs
@@ -16,7 +16,7 @@ using OpenRA.Primitives;
 
 namespace OpenRA.Network
 {
-	public class ReplayConnection : IConnection
+	public sealed class ReplayConnection : IConnection
 	{
 		class Chunk
 		{
diff --git a/OpenRA.Game/Network/ReplayRecorderConnection.cs b/OpenRA.Game/Network/ReplayRecorderConnection.cs
index 15a843d010..57b907ef8b 100644
--- a/OpenRA.Game/Network/ReplayRecorderConnection.cs
+++ b/OpenRA.Game/Network/ReplayRecorderConnection.cs
@@ -17,7 +17,7 @@ using OpenRA.Widgets;
 
 namespace OpenRA.Network
 {
-	class ReplayRecorderConnection : IConnection, IDisposable
+	sealed class ReplayRecorderConnection : IConnection
 	{
 		public ReplayMetadata Metadata;
 
@@ -98,30 +98,24 @@ namespace OpenRA.Network
 		}
 
 		bool disposed;
-		protected void Dispose(bool disposing)
-		{
-			if (disposed)
-				return;
-
-			if (disposing)
-			{
-				if (Metadata != null)
-				{
-					if (Metadata.GameInfo != null)
-						Metadata.GameInfo.EndTimeUtc = DateTime.UtcNow;
-					Metadata.Write(writer);
-				}
-				writer.Close();
-				inner.Dispose();
-			}
-
-			disposed = true;
-		}
 
 		public void Dispose()
 		{
-			Dispose(true);
-			GC.SuppressFinalize(this);
+			if (disposed)
+				return;
+			disposed = true;
+
+			if (Metadata != null)
+			{
+				if (Metadata.GameInfo != null)
+					Metadata.GameInfo.EndTimeUtc = DateTime.UtcNow;
+				Metadata.Write(writer);
+			}
+
+			if (preStartBuffer != null)
+				preStartBuffer.Dispose();
+			writer.Close();
+			inner.Dispose();
 		}
 	}
 }
diff --git a/OpenRA.Game/Primitives/DisposableAction.cs b/OpenRA.Game/Primitives/DisposableAction.cs
index 4734935f59..333f5ceeb9 100644
--- a/OpenRA.Game/Primitives/DisposableAction.cs
+++ b/OpenRA.Game/Primitives/DisposableAction.cs
@@ -12,7 +12,7 @@ using System;
 
 namespace OpenRA.Primitives
 {
-	public class DisposableAction : IDisposable
+	public sealed class DisposableAction : IDisposable
 	{
 		public DisposableAction(Action onDispose, Action onFinalize)
 		{
@@ -26,7 +26,8 @@ namespace OpenRA.Primitives
 
 		public void Dispose()
 		{
-			if (disposed) return;
+			if (disposed)
+				return;
 			disposed = true;
 			onDispose();
 			GC.SuppressFinalize(this);
diff --git a/OpenRA.Game/Scripting/ScriptContext.cs b/OpenRA.Game/Scripting/ScriptContext.cs
index 7f3eb45a75..44dc9cb417 100644
--- a/OpenRA.Game/Scripting/ScriptContext.cs
+++ b/OpenRA.Game/Scripting/ScriptContext.cs
@@ -81,12 +81,11 @@ namespace OpenRA.Scripting
 		public ScriptGlobalAttribute(string name) { Name = name; }
 	}
 
-	public class ScriptContext : IDisposable
+	public sealed class ScriptContext : IDisposable
 	{
 		public World World { get; private set; }
 		public WorldRenderer WorldRenderer { get; private set; }
 
-		bool disposed;
 		readonly MemoryConstrainedLuaRuntime runtime;
 		readonly LuaFunction tick;
 
@@ -100,6 +99,8 @@ namespace OpenRA.Scripting
 		public readonly Cache<ActorInfo, Type[]> ActorCommands;
 		public readonly Type[] PlayerCommands;
 
+		bool disposed;
+
 		public ScriptContext(World world, WorldRenderer worldRenderer,
 			IEnumerable<string> scripts)
 		{
@@ -196,27 +197,13 @@ namespace OpenRA.Scripting
 				tick.Call().Dispose();
 		}
 
-		protected void Dispose(bool disposing)
+		public void Dispose()
 		{
 			if (disposed)
 				return;
-
-			if (disposing)
-				runtime.Dispose();
-
 			disposed = true;
-		}
-
-		public void Dispose()
-		{
-			Dispose(true);
-			GC.SuppressFinalize(this);
-		}
-
-		~ScriptContext()
-		{
-			// Dispose unmanaged resources only
-			Dispose(false);
+			if (runtime != null)
+				runtime.Dispose();
 		}
 
 		static Type[] ExtractRequiredTypes(Type t)
diff --git a/OpenRA.Game/Sound.cs b/OpenRA.Game/Sound.cs
index e996086076..cbf3e5f320 100644
--- a/OpenRA.Game/Sound.cs
+++ b/OpenRA.Game/Sound.cs
@@ -39,9 +39,11 @@ namespace OpenRA
 			}
 
 			if (filename.ToLowerInvariant().EndsWith("wav"))
-				return LoadWave(new WavLoader(GlobalFileSystem.Open(filename)));
+				using (var s = GlobalFileSystem.Open(filename))
+					return LoadWave(new WavLoader(s));
 
-			return LoadSoundRaw(AudLoader.LoadSound(GlobalFileSystem.Open(filename)));
+			using (var s = GlobalFileSystem.Open(filename))
+				return LoadSoundRaw(AudLoader.LoadSound(s));
 		}
 
 		static ISoundSource LoadWave(WavLoader wave)
diff --git a/OpenRA.Game/Support/PerfHistory.cs b/OpenRA.Game/Support/PerfHistory.cs
index 3812b94c86..4f9c00f32f 100644
--- a/OpenRA.Game/Support/PerfHistory.cs
+++ b/OpenRA.Game/Support/PerfHistory.cs
@@ -105,7 +105,7 @@ namespace OpenRA.Support
 		}
 	}
 
-	public class PerfSample : IDisposable
+	public sealed class PerfSample : IDisposable
 	{
 		readonly Stopwatch sw = Stopwatch.StartNew();
 		readonly string Item;
diff --git a/OpenRA.Game/Support/PerfTimer.cs b/OpenRA.Game/Support/PerfTimer.cs
index 05514ba73a..1492c436d8 100755
--- a/OpenRA.Game/Support/PerfTimer.cs
+++ b/OpenRA.Game/Support/PerfTimer.cs
@@ -16,7 +16,7 @@ using System.Threading;
 
 namespace OpenRA.Support
 {
-	public class PerfTimer : IDisposable
+	public sealed class PerfTimer : IDisposable
 	{
 		readonly string name;
 		readonly float thresholdMs;
diff --git a/OpenRA.Game/Support/Program.cs b/OpenRA.Game/Support/Program.cs
index baf4d2cfd5..9204a19c79 100644
--- a/OpenRA.Game/Support/Program.cs
+++ b/OpenRA.Game/Support/Program.cs
@@ -57,7 +57,7 @@ namespace OpenRA
 
 			if (Game.Settings.Debug.ShowFatalErrorDialog && !Game.Settings.Server.Dedicated)
 			{
-				Game.Renderer.Device.Quit();
+				Game.Renderer.Device.Dispose();
 				Platform.ShowFatalErrorDialog();
 			}
 		}
diff --git a/OpenRA.Irc/IrcClient.cs b/OpenRA.Irc/IrcClient.cs
index c2f06cfbc6..6f655566d3 100644
--- a/OpenRA.Irc/IrcClient.cs
+++ b/OpenRA.Irc/IrcClient.cs
@@ -17,7 +17,7 @@ using OpenRA.Primitives;
 
 namespace OpenRA.Irc
 {
-	public class IrcClient : IDisposable
+	public sealed class IrcClient : IDisposable
 	{
 		public static readonly IrcClient Instance = new IrcClient();
 
@@ -252,14 +252,15 @@ namespace OpenRA.Irc
 
 			ConnectionState = IrcConnectionState.Disconnecting;
 			OnDisconnecting();
-			connection.Close();
+			if (connection != null)
+				connection.Close();
 			ConnectionState = IrcConnectionState.Disconnected;
 			OnDisconnect();
 			LocalUser = null;
 			connection = null;
 		}
 
-		void IDisposable.Dispose()
+		public void Dispose()
 		{
 			Disconnect();
 		}
diff --git a/OpenRA.Irc/IrcConnection.cs b/OpenRA.Irc/IrcConnection.cs
index ae9679f83b..66c14096bb 100644
--- a/OpenRA.Irc/IrcConnection.cs
+++ b/OpenRA.Irc/IrcConnection.cs
@@ -14,7 +14,7 @@ using System.Net.Sockets;
 
 namespace OpenRA.Irc
 {
-	public class IrcConnection : IDisposable
+	public sealed class IrcConnection : IDisposable
 	{
 		TcpClient socket;
 		Stream stream;
@@ -49,14 +49,8 @@ namespace OpenRA.Irc
 
 		public void Close()
 		{
-			CloseImpl();
-			GC.SuppressFinalize(this);
-		}
-
-		void CloseImpl()
-		{
-			if (disposed) return;
-
+			if (disposed)
+				return;
 			disposed = true;
 			if (socket != null) socket.Close();
 			if (stream != null) stream.Close();
@@ -64,16 +58,11 @@ namespace OpenRA.Irc
 			if (reader != null) reader.Close();
 		}
 
-		void IDisposable.Dispose()
+		public void Dispose()
 		{
 			Close();
 		}
 
-		~IrcConnection()
-		{
-			CloseImpl();
-		}
-
 		void CheckDisposed()
 		{
 			if (disposed)
diff --git a/OpenRA.Mods.RA/Move/PathSearch.cs b/OpenRA.Mods.RA/Move/PathSearch.cs
index 0c198eb9a9..9036463986 100755
--- a/OpenRA.Mods.RA/Move/PathSearch.cs
+++ b/OpenRA.Mods.RA/Move/PathSearch.cs
@@ -15,7 +15,7 @@ using OpenRA.Primitives;
 
 namespace OpenRA.Mods.RA.Move
 {
-	public class PathSearch : IDisposable
+	public sealed class PathSearch : IDisposable
 	{
 		World world;
 		public CellInfo[,] cellInfo;
@@ -291,11 +291,12 @@ namespace OpenRA.Mods.RA.Move
 		{
 			if (disposed)
 				return;
-
 			disposed = true;
-			GC.SuppressFinalize(this);
+
 			PutBackIntoPool(cellInfo);
 			cellInfo = null;
+
+			GC.SuppressFinalize(this);
 		}
 
 		~PathSearch() { Dispose(); }
diff --git a/OpenRA.Mods.RA/Scripting/CallLuaFunc.cs b/OpenRA.Mods.RA/Scripting/CallLuaFunc.cs
index 7df12f1c30..71dffe2827 100644
--- a/OpenRA.Mods.RA/Scripting/CallLuaFunc.cs
+++ b/OpenRA.Mods.RA/Scripting/CallLuaFunc.cs
@@ -15,7 +15,7 @@ using OpenRA.Traits;
 
 namespace OpenRA.Mods.RA.Activities
 {
-	public class CallLuaFunc : Activity, IDisposable
+	public sealed class CallLuaFunc : Activity, IDisposable
 	{
 		LuaFunction function;
 
@@ -39,28 +39,11 @@ namespace OpenRA.Mods.RA.Activities
 			base.Cancel(self);
 		}
 
-		protected void Dispose(bool disposing)
-		{
-			if (function == null)
-				return;
-
-			if (disposing)
-			{
-				function.Dispose();
-				function = null;
-			}
-		}
-
 		public void Dispose()
 		{
-			Dispose(true);
-			GC.SuppressFinalize(this);
-		}
-
-		~CallLuaFunc()
-		{
-			// Dispose unmanaged resources only
-			Dispose(false);
+			if (function == null) return;
+			function.Dispose();
+			function = null;
 		}
 	}
 }
diff --git a/OpenRA.Mods.RA/Scripting/LuaScript.cs b/OpenRA.Mods.RA/Scripting/LuaScript.cs
index 0e27b3b445..9ea1c2831b 100644
--- a/OpenRA.Mods.RA/Scripting/LuaScript.cs
+++ b/OpenRA.Mods.RA/Scripting/LuaScript.cs
@@ -8,6 +8,7 @@
  */
 #endregion
 
+using System;
 using OpenRA.Graphics;
 using OpenRA.Scripting;
 using OpenRA.Traits;
@@ -21,7 +22,7 @@ namespace OpenRA.Mods.RA.Scripting
 		public object Create(ActorInitializer init) { return new LuaScript(this); }
 	}
 
-	public class LuaScript : ITick, IWorldLoaded
+	public sealed class LuaScript : ITick, IWorldLoaded, IDisposable
 	{
 		readonly LuaScriptInfo info;
 		ScriptContext context;
@@ -42,5 +43,11 @@ namespace OpenRA.Mods.RA.Scripting
 		{
 			context.Tick(self);
 		}
+
+		public void Dispose()
+		{
+			if (context != null)
+				context.Dispose();
+		}
 	}
 }
diff --git a/OpenRA.Mods.RA/Scripting/LuaScriptContext.cs b/OpenRA.Mods.RA/Scripting/LuaScriptContext.cs
index 714aaab803..0c301e4919 100644
--- a/OpenRA.Mods.RA/Scripting/LuaScriptContext.cs
+++ b/OpenRA.Mods.RA/Scripting/LuaScriptContext.cs
@@ -18,7 +18,7 @@ using OpenRA.Primitives;
 
 namespace OpenRA.Mods.RA.Scripting
 {
-	public class LuaScriptContext : IDisposable
+	public sealed class LuaScriptContext : IDisposable
 	{
 		public Lua Lua { get; private set; }
 		readonly Cache<string, LuaFunction> functionCache;
@@ -133,19 +133,9 @@ namespace OpenRA.Mods.RA.Scripting
 		}
 
 		public void Dispose()
-		{
-			if (Lua == null)
-				return;
-
-			GC.SuppressFinalize(this);
-			Lua.Dispose();
-			Lua = null;
-		}
-
-		~LuaScriptContext()
 		{
 			if (Lua != null)
-				Game.RunAfterTick(Dispose);
+				Lua.Dispose();
 		}
 	}
 }
diff --git a/OpenRA.Mods.RA/Scripting/LuaScriptInterface.cs b/OpenRA.Mods.RA/Scripting/LuaScriptInterface.cs
index c2f65552ed..ec0607dc34 100644
--- a/OpenRA.Mods.RA/Scripting/LuaScriptInterface.cs
+++ b/OpenRA.Mods.RA/Scripting/LuaScriptInterface.cs
@@ -32,7 +32,7 @@ namespace OpenRA.Mods.RA.Scripting
 		public object Create(ActorInitializer init) { return new LuaScriptInterface(this); }
 	}
 
-	public class LuaScriptInterface : IWorldLoaded, ITick
+	public sealed class LuaScriptInterface : IWorldLoaded, ITick, IDisposable
 	{
 		World world;
 		SpawnMapActors sma;
@@ -90,6 +90,11 @@ namespace OpenRA.Mods.RA.Scripting
 				context.InvokeLuaFunction("Tick");
 		}
 
+		public void Dispose()
+		{
+			context.Dispose();
+		}
+
 		[LuaGlobal]
 		public object New(string typeName, LuaTable args)
 		{
diff --git a/OpenRA.Mods.RA/Scripting/ScriptTriggers.cs b/OpenRA.Mods.RA/Scripting/ScriptTriggers.cs
index 7056795510..d68e9c2112 100644
--- a/OpenRA.Mods.RA/Scripting/ScriptTriggers.cs
+++ b/OpenRA.Mods.RA/Scripting/ScriptTriggers.cs
@@ -21,7 +21,7 @@ namespace OpenRA.Mods.RA.Scripting
 	[Desc("Allows map scripts to attach triggers to this actor via the Triggers global.")]
 	public class ScriptTriggersInfo : TraitInfo<ScriptTriggers> { }
 
-	public class ScriptTriggers : INotifyIdle, INotifyDamage, INotifyKilled, INotifyProduction, IDisposable
+	public sealed class ScriptTriggers : INotifyIdle, INotifyDamage, INotifyKilled, INotifyProduction, IDisposable
 	{
 		public event Action<Actor> OnKilledInternal = _ => {};
 
@@ -100,37 +100,11 @@ namespace OpenRA.Mods.RA.Scripting
 			}
 		}
 
-		bool disposed;
-
-		protected void Dispose(bool disposing)
-		{
-			if (disposed)
-				return;
-
-			if (disposing)
-			{
-				var toDispose = new [] { onIdle, onDamaged, onKilled, onProduction };
-
-				foreach (var f in toDispose.SelectMany(f => f))
-					f.First.Dispose();
-
-				foreach (var l in toDispose)
-					l.Clear();
-			}
-
-			disposed = true;
-		}
-
 		public void Dispose()
 		{
-			Dispose(true);
-			GC.SuppressFinalize(this);
-		}
-
-		~ScriptTriggers()
-		{
-			// Dispose unmanaged resources only
-			Dispose(false);
+			var pairs = new[] { onIdle, onDamaged, onKilled, onProduction };
+			pairs.SelectMany(l => l).Select(p => p.First).Do(f => f.Dispose());
+			pairs.Do(l => l.Clear());
 		}
 	}
 }
diff --git a/OpenRA.Mods.RA/Widgets/HueSliderWidget.cs b/OpenRA.Mods.RA/Widgets/HueSliderWidget.cs
index 7d0fdfd9bc..657145f1ea 100755
--- a/OpenRA.Mods.RA/Widgets/HueSliderWidget.cs
+++ b/OpenRA.Mods.RA/Widgets/HueSliderWidget.cs
@@ -18,7 +18,6 @@ namespace OpenRA.Mods.RA.Widgets
 {
 	public class HueSliderWidget : SliderWidget
 	{
-		Bitmap hueBitmap;
 		Sprite hueSprite;
 
 		public HueSliderWidget() {}
@@ -28,20 +27,22 @@ namespace OpenRA.Mods.RA.Widgets
 		{
 			base.Initialize(args);
 
-			hueBitmap = new Bitmap(256, 256);
-			hueSprite = new Sprite(new Sheet(new Size(256, 256)), new Rectangle(0, 0, 256, 1), TextureChannel.Alpha);
-
-			var bitmapData = hueBitmap.LockBits(hueBitmap.Bounds(),
-				ImageLockMode.ReadWrite, PixelFormat.Format32bppArgb);
-			unsafe
+			using (var hueBitmap = new Bitmap(256, 256))
 			{
-				int* c = (int*)bitmapData.Scan0;
-				for (var h = 0; h < 256; h++)
-					*(c + h) = HSLColor.FromHSV(h/255f, 1, 1).RGB.ToArgb();
-			}
-			hueBitmap.UnlockBits(bitmapData);
+				hueSprite = new Sprite(new Sheet(new Size(256, 256)), new Rectangle(0, 0, 256, 1), TextureChannel.Alpha);
 
-			hueSprite.sheet.Texture.SetData(hueBitmap);
+				var bitmapData = hueBitmap.LockBits(hueBitmap.Bounds(),
+					ImageLockMode.ReadWrite, PixelFormat.Format32bppArgb);
+				unsafe
+				{
+					int* c = (int*)bitmapData.Scan0;
+					for (var h = 0; h < 256; h++)
+						*(c + h) = HSLColor.FromHSV(h / 255f, 1, 1).RGB.ToArgb();
+				}
+				hueBitmap.UnlockBits(bitmapData);
+
+				hueSprite.sheet.Texture.SetData(hueBitmap);
+			}
 		}
 
 		public override void Draw()
diff --git a/OpenRA.Mods.RA/Widgets/RadarWidget.cs b/OpenRA.Mods.RA/Widgets/RadarWidget.cs
index 4030463dd9..4a0a5e99c4 100755
--- a/OpenRA.Mods.RA/Widgets/RadarWidget.cs
+++ b/OpenRA.Mods.RA/Widgets/RadarWidget.cs
@@ -68,16 +68,18 @@ namespace OpenRA.Mods.RA.Widgets
 			mapRect = new Rectangle(previewOrigin.X, previewOrigin.Y, (int)(previewScale * width), (int)(previewScale * height));
 
 			// Only needs to be done once
-			var terrainBitmap = Minimap.TerrainBitmap(world.Map.Rules.TileSets[world.Map.Tileset], world.Map);
-			var r = new Rectangle(0, 0, width, height);
-			var s = new Size(terrainBitmap.Width, terrainBitmap.Height);
-			terrainSprite = new Sprite(new Sheet(s), r, TextureChannel.Alpha);
-			terrainSprite.sheet.Texture.SetData(terrainBitmap);
+			using (var terrainBitmap = Minimap.TerrainBitmap(world.Map.Rules.TileSets[world.Map.Tileset], world.Map))
+			{
+				var r = new Rectangle(0, 0, width, height);
+				var s = new Size(terrainBitmap.Width, terrainBitmap.Height);
+				terrainSprite = new Sprite(new Sheet(s), r, TextureChannel.Alpha);
+				terrainSprite.sheet.Texture.SetData(terrainBitmap);
 
-			// Data is set in Tick()
-			customTerrainSprite = new Sprite(new Sheet(s), r, TextureChannel.Alpha);
-			actorSprite = new Sprite(new Sheet(s), r, TextureChannel.Alpha);
-			shroudSprite = new Sprite(new Sheet(s), r, TextureChannel.Alpha);
+				// Data is set in Tick()
+				customTerrainSprite = new Sprite(new Sheet(s), r, TextureChannel.Alpha);
+				actorSprite = new Sprite(new Sheet(s), r, TextureChannel.Alpha);
+				shroudSprite = new Sprite(new Sheet(s), r, TextureChannel.Alpha);
+			}
 		}
 
 		public override string GetCursor(int2 pos)
@@ -197,14 +199,17 @@ namespace OpenRA.Mods.RA.Widgets
 			if (updateTicks <= 0)
 			{
 				updateTicks = 12;
-				customTerrainSprite.sheet.Texture.SetData(Minimap.CustomTerrainBitmap(world));
+				using (var bitmap = Minimap.CustomTerrainBitmap(world))
+					customTerrainSprite.sheet.Texture.SetData(bitmap);
 			}
 
 			if (updateTicks == 8)
-				actorSprite.sheet.Texture.SetData(Minimap.ActorsBitmap(world));
+				using (var bitmap = Minimap.ActorsBitmap(world))
+					actorSprite.sheet.Texture.SetData(bitmap);
 
 			if (updateTicks == 4)
-				shroudSprite.sheet.Texture.SetData(Minimap.ShroudBitmap(world));
+				using (var bitmap = Minimap.ShroudBitmap(world))
+					shroudSprite.sheet.Texture.SetData(bitmap);
 
 			// Enable/Disable the radar
 			var enabled = IsEnabled();
diff --git a/OpenRA.Renderer.Null/NullGraphicsDevice.cs b/OpenRA.Renderer.Null/NullGraphicsDevice.cs
index 8a24761c84..3469b8a170 100644
--- a/OpenRA.Renderer.Null/NullGraphicsDevice.cs
+++ b/OpenRA.Renderer.Null/NullGraphicsDevice.cs
@@ -25,7 +25,7 @@ namespace OpenRA.Renderer.Null
 		}
 	}
 
-	public class NullGraphicsDevice : IGraphicsDevice
+	public sealed class NullGraphicsDevice : IGraphicsDevice
 	{
 		public Size WindowSize { get; internal set; }
 
@@ -35,7 +35,7 @@ namespace OpenRA.Renderer.Null
 			WindowSize = size;
 		}
 
-		public void Quit() { }
+		public void Dispose() { }
 
 		public void EnableScissor(int left, int top, int width, int height) { }
 		public void DisableScissor() { }
diff --git a/OpenRA.Renderer.Sdl2/Sdl2GraphicsDevice.cs b/OpenRA.Renderer.Sdl2/Sdl2GraphicsDevice.cs
index 543e946b2b..c9e3473932 100755
--- a/OpenRA.Renderer.Sdl2/Sdl2GraphicsDevice.cs
+++ b/OpenRA.Renderer.Sdl2/Sdl2GraphicsDevice.cs
@@ -29,11 +29,12 @@ namespace OpenRA.Renderer.Sdl2
 		}
 	}
 
-	public class Sdl2GraphicsDevice : IGraphicsDevice
+	public sealed class Sdl2GraphicsDevice : IGraphicsDevice
 	{
 		Size size;
 		Sdl2Input input;
 		IntPtr context, window;
+		bool disposed;
 
 		public Size WindowSize { get { return size; } }
 
@@ -101,10 +102,21 @@ namespace OpenRA.Renderer.Sdl2
 			input = new Sdl2Input();
 		}
 
-		public virtual void Quit()
+		public void Dispose()
 		{
-			SDL.SDL_GL_DeleteContext(context);
-			SDL.SDL_DestroyWindow(window);
+			if (disposed)
+				return;
+			disposed = true;
+			if (context != IntPtr.Zero)
+			{
+				SDL.SDL_GL_DeleteContext(context);
+				context = IntPtr.Zero;
+			}
+			if (window != IntPtr.Zero)
+			{
+				SDL.SDL_DestroyWindow(window);
+				window = IntPtr.Zero;
+			}
 			SDL.SDL_Quit();
 		}
 
diff --git a/OpenRA.Renderer.Sdl2/Texture.cs b/OpenRA.Renderer.Sdl2/Texture.cs
index f000235aba..943576cfdf 100644
--- a/OpenRA.Renderer.Sdl2/Texture.cs
+++ b/OpenRA.Renderer.Sdl2/Texture.cs
@@ -106,18 +106,29 @@ namespace OpenRA.Renderer.Sdl2
 
 		public void SetData(Bitmap bitmap)
 		{
+			bool allocatedBitmap = false;
 			if (!Exts.IsPowerOf2(bitmap.Width) || !Exts.IsPowerOf2(bitmap.Height))
+			{
 				bitmap = new Bitmap(bitmap, bitmap.Size.NextPowerOf2());
+				allocatedBitmap = true;
+			}
+			try
+			{
+				size = new Size(bitmap.Width, bitmap.Height);
+				var bits = bitmap.LockBits(bitmap.Bounds(),
+					ImageLockMode.ReadOnly, System.Drawing.Imaging.PixelFormat.Format32bppArgb);
 
-			size = new Size(bitmap.Width, bitmap.Height);
-			var bits = bitmap.LockBits(bitmap.Bounds(),
-				ImageLockMode.ReadOnly,	System.Drawing.Imaging.PixelFormat.Format32bppArgb);
-
-			PrepareTexture();
-			GL.TexImage2D(TextureTarget.Texture2D, 0, PixelInternalFormat.Rgba8, bits.Width, bits.Height,
-				0, OpenTK.Graphics.OpenGL.PixelFormat.Bgra, PixelType.UnsignedByte, bits.Scan0); // TODO: weird strides
-			ErrorHandler.CheckGlError();
-			bitmap.UnlockBits(bits);
+				PrepareTexture();
+				GL.TexImage2D(TextureTarget.Texture2D, 0, PixelInternalFormat.Rgba8, bits.Width, bits.Height,
+					0, OpenTK.Graphics.OpenGL.PixelFormat.Bgra, PixelType.UnsignedByte, bits.Scan0); // TODO: weird strides
+				ErrorHandler.CheckGlError();
+				bitmap.UnlockBits(bits);
+			}
+			finally
+			{
+				if (allocatedBitmap)
+					bitmap.Dispose();
+			}
 		}
 
 		public byte[] GetData()
diff --git a/OpenRA.TilesetBuilder/FormBuilder.cs b/OpenRA.TilesetBuilder/FormBuilder.cs
index 9370d91a69..25b587b96c 100644
--- a/OpenRA.TilesetBuilder/FormBuilder.cs
+++ b/OpenRA.TilesetBuilder/FormBuilder.cs
@@ -51,8 +51,9 @@ namespace OpenRA.TilesetBuilder
 				this.size = TileSize;
 				surface1.TileSize = TileSize;
 
-				Bitmap fbitmap = new Bitmap(ImageFile);
-				Bitmap rbitmap = fbitmap.Clone(new Rectangle(0, 0, fbitmap.Width, fbitmap.Height),
+				Bitmap rbitmap;
+				using (var fbitmap = new Bitmap(ImageFile))
+					rbitmap = fbitmap.Clone(new Rectangle(0, 0, fbitmap.Width, fbitmap.Height),
 						fbitmap.PixelFormat);
 
 				int[] shadowIndex = { };
diff --git a/OpenRA.Utility/LegacyMapImporter.cs b/OpenRA.Utility/LegacyMapImporter.cs
index 429d44fab4..c17c862e9d 100644
--- a/OpenRA.Utility/LegacyMapImporter.cs
+++ b/OpenRA.Utility/LegacyMapImporter.cs
@@ -162,7 +162,8 @@ namespace OpenRA.Utility
 			else
 			{
 				// CnC
-				UnpackCncTileData(GlobalFileSystem.Open(iniFile.Substring(0, iniFile.Length - 4) + ".bin"));
+				using (var s = GlobalFileSystem.Open(iniFile.Substring(0, iniFile.Length - 4) + ".bin"))
+					UnpackCncTileData(s);
 				ReadCncOverlay(file);
 				ReadCncTrees(file);
 			}