diff --git a/MimeKit/AsyncMimeParser.cs b/MimeKit/AsyncMimeParser.cs
index 27b5e234ed..45b73c605f 100644
--- a/MimeKit/AsyncMimeParser.cs
+++ b/MimeKit/AsyncMimeParser.cs
@@ -363,7 +363,7 @@ async Task ConstructMessagePartAsync (MessagePart rfc822, MimeEntityEndEventArgs
 		async Task MultipartScanPreambleAsync (Multipart multipart, CancellationToken cancellationToken)
 		{
 			using (var memory = new MemoryStream ()) {
-				long offset = GetOffset (inputIndex);
+				//long offset = GetOffset (inputIndex);
 
 				//OnMultipartPreambleBegin (multipart, offset);
 				await ScanContentAsync (memory, false, cancellationToken).ConfigureAwait (false);
@@ -375,7 +375,7 @@ async Task MultipartScanPreambleAsync (Multipart multipart, CancellationToken ca
 		async Task MultipartScanEpilogueAsync (Multipart multipart, CancellationToken cancellationToken)
 		{
 			using (var memory = new MemoryStream ()) {
-				long offset = GetOffset (inputIndex);
+				//long offset = GetOffset (inputIndex);
 
 				//OnMultipartEpilogueBegin (multipart, offset);
 				var result = await ScanContentAsync (memory, true, cancellationToken).ConfigureAwait (false);
diff --git a/MimeKit/MimeParser.cs b/MimeKit/MimeParser.cs
index f87d283966..9027e1b536 100644
--- a/MimeKit/MimeParser.cs
+++ b/MimeKit/MimeParser.cs
@@ -1551,7 +1551,7 @@ unsafe void ConstructMessagePart (MessagePart rfc822, MimeEntityEndEventArgs arg
 		unsafe void MultipartScanPreamble (Multipart multipart, byte* inbuf, CancellationToken cancellationToken)
 		{
 			using (var memory = new MemoryStream ()) {
-				long offset = GetOffset (inputIndex);
+				//long offset = GetOffset (inputIndex);
 
 				//OnMultipartPreambleBegin (multipart, offset);
 				ScanContent (inbuf, memory, false, cancellationToken);
@@ -1563,7 +1563,7 @@ unsafe void MultipartScanPreamble (Multipart multipart, byte* inbuf, Cancellatio
 		unsafe void MultipartScanEpilogue (Multipart multipart, byte* inbuf, CancellationToken cancellationToken)
 		{
 			using (var memory = new MemoryStream ()) {
-				long offset = GetOffset (inputIndex);
+				//long offset = GetOffset (inputIndex);
 
 				//OnMultipartEpilogueBegin (multipart, offset);
 				var result = ScanContent (inbuf, memory, true, cancellationToken);
diff --git a/MimeKit/Utils/ParseUtils.cs b/MimeKit/Utils/ParseUtils.cs
index 714eb864ff..44e520f1ab 100644
--- a/MimeKit/Utils/ParseUtils.cs
+++ b/MimeKit/Utils/ParseUtils.cs
@@ -139,7 +139,6 @@ public static bool SkipComment (byte[] text, ref int index, int endIndex)
 						depth++;
 					else if (text[index] == (byte) ')')
 						depth--;
-					escaped = false;
 				} else {
 					escaped = false;
 				}
@@ -165,7 +164,6 @@ public static bool SkipComment (string text, ref int index, int endIndex)
 						depth++;
 					else if (text[index] == ')')
 						depth--;
-					escaped = false;
 				} else {
 					escaped = false;
 				}
diff --git a/MimeKit/Utils/StringBuilderExtensions.cs b/MimeKit/Utils/StringBuilderExtensions.cs
index f7231f330d..88b86cdceb 100644
--- a/MimeKit/Utils/StringBuilderExtensions.cs
+++ b/MimeKit/Utils/StringBuilderExtensions.cs
@@ -143,7 +143,7 @@ public static void Append (this StringBuilder text, ReadOnlySpan<char> value)
 
 		public static void Append (this StringBuilder sb, StringBuilder value)
 		{
-			sb.Append (value.ToString ());
+			sb.Append (value);
 		}
 #endif