diff --git a/editor/libeditor/base/nsEditor.cpp b/editor/libeditor/base/nsEditor.cpp
index fc661f07f21e..c461bc93e006 100644
--- a/editor/libeditor/base/nsEditor.cpp
+++ b/editor/libeditor/base/nsEditor.cpp
@@ -41,6 +41,7 @@
 #include "pratom.h"
 #include "nsIDOMDocument.h"
 #include "nsIPref.h"
+#include "nsUnicharUtils.h"
 
 #include "nsIDOMText.h"
 #include "nsIDOMElement.h"
@@ -3452,7 +3453,7 @@ nsEditor::NodeIsType(nsIDOMNode *aNode, nsIAtom *aTag)
     element->GetTagName(tag);
     const PRUnichar *unicodeString;
     aTag->GetUnicode(&unicodeString);
-    if (tag.EqualsIgnoreCase(nsAutoString(unicodeString)))
+    if (tag.Equals(unicodeString, nsCaseInsensitiveStringComparator()))
     {
       return PR_TRUE;
     }
diff --git a/intl/locale/src/mac/nsDateTimeFormatMac.cpp b/intl/locale/src/mac/nsDateTimeFormatMac.cpp
index 852ffd1040e6..d8f77ddf9d68 100644
--- a/intl/locale/src/mac/nsDateTimeFormatMac.cpp
+++ b/intl/locale/src/mac/nsDateTimeFormatMac.cpp
@@ -52,6 +52,7 @@
 #include "nsCRT.h"
 #include "plstr.h"
 #include "prmem.h"
+#include "nsUnicharUtils.h"
 
 ////////////////////////////////////////////////////////////////////////////////
 
@@ -247,7 +248,9 @@ nsresult nsDateTimeFormatMac::Initialize(nsILocale* locale)
   else {
     res = locale->GetCategory(aCategory.get(), &aLocaleUnichar);
     if (NS_SUCCEEDED(res) && NULL != aLocaleUnichar) {
-      if (mLocale.Length() && mLocale.EqualsIgnoreCase(nsAutoString(aLocaleUnichar))) {
+      if (!mLocale.IsEmpty() &&
+          mLocale.Equals(aLocaleUnichar,
+                         nsCaseInsensitiveStringComparator())) {
         nsMemory::Free(aLocaleUnichar);
         return NS_OK;
       }
diff --git a/intl/locale/src/unix/nsDateTimeFormatUnix.cpp b/intl/locale/src/unix/nsDateTimeFormatUnix.cpp
index 559f47f3781e..9f2a71cb08ea 100644
--- a/intl/locale/src/unix/nsDateTimeFormatUnix.cpp
+++ b/intl/locale/src/unix/nsDateTimeFormatUnix.cpp
@@ -47,6 +47,7 @@
 #include "nsIPlatformCharset.h"
 #include "nsIPosixLocale.h"
 #include "nsCRT.h"
+#include "nsUnicharUtils.h"
 
 NS_IMPL_THREADSAFE_ISUPPORTS1(nsDateTimeFormatUnix, nsIDateTimeFormat);
 
@@ -67,7 +68,9 @@ nsresult nsDateTimeFormatUnix::Initialize(nsILocale* locale)
   else {
     res = locale->GetCategory(aCategory.get(), &aLocaleUnichar);
     if (NS_SUCCEEDED(res) && NULL != aLocaleUnichar) {
-      if (mLocale.Length() && mLocale.EqualsIgnoreCase(nsAutoString(aLocaleUnichar))) {
+      if (!mLocale.IsEmpty() &&
+          mLocale.Equals(aLocaleUnichar,
+                         nsCaseInsensitiveStringComparator())) {
         nsMemory::Free(aLocaleUnichar);
         return NS_OK;
       }
diff --git a/mailnews/imap/src/nsImapMailFolder.cpp b/mailnews/imap/src/nsImapMailFolder.cpp
index b56b2014ccbe..bce97ce47fc6 100644
--- a/mailnews/imap/src/nsImapMailFolder.cpp
+++ b/mailnews/imap/src/nsImapMailFolder.cpp
@@ -355,11 +355,12 @@ NS_IMETHODIMP nsImapMailFolder::AddSubfolderWithPath(nsAutoString *name, nsIFile
 
   if(NS_SUCCEEDED(rv))
   {
-    if(isServer && (Compare(*name,
-                            NS_LITERAL_STRING("Inbox"),
-                            nsCaseInsensitiveStringComparator()) == 0))
+    if(isServer &&
+       name->Equals(NS_LITERAL_STRING("Inbox"),
+                    nsCaseInsensitiveStringComparator()))
       flags |= MSG_FOLDER_FLAG_INBOX;
-    else if((isServer || isParentInbox) && name->EqualsIgnoreCase(nsAutoString(kTrashName)))
+    else if((isServer || isParentInbox) && name->Equals(kTrashName,
+                                                        nsCaseInsensitiveStringComparator()))
       flags |= MSG_FOLDER_FLAG_TRASH;
 #if 0
     else if(name->EqualsIgnoreCase(kSentName))
diff --git a/mailnews/local/src/nsLocalMailFolder.cpp b/mailnews/local/src/nsLocalMailFolder.cpp
index 915f43010248..11701922e957 100644
--- a/mailnews/local/src/nsLocalMailFolder.cpp
+++ b/mailnews/local/src/nsLocalMailFolder.cpp
@@ -295,15 +295,15 @@ NS_IMETHODIMP nsMsgLocalMailFolder::AddSubfolder(nsAutoString *name,
 	//Only set these is these are top level children.
 	if(NS_SUCCEEDED(rv) && isServer)
 	{
-		if(name->EqualsIgnoreCase(nsAutoString(kInboxName)))
+		if(name->Equals(kInboxName, nsCaseInsensitiveStringComparator()))
 		{
 			flags |= MSG_FOLDER_FLAG_INBOX;
                         SetBiffState(nsIMsgFolder::nsMsgBiffState_Unknown);
 		}
-		else if (name->EqualsIgnoreCase(nsAutoString(kTrashName)))
+		else if (name->Equals(kTrashName, nsCaseInsensitiveStringComparator()))
 			flags |= MSG_FOLDER_FLAG_TRASH;
-		else if (name->EqualsIgnoreCase(nsAutoString(kUnsentName))
-             || Compare(*name, NS_LITERAL_STRING("Outbox"), nsCaseInsensitiveStringComparator()) == 0)
+		else if (name->Equals(kUnsentName, nsCaseInsensitiveStringComparator()) ||
+			name->Equals(NS_LITERAL_STRING("Outbox"), nsCaseInsensitiveStringComparator()))
 			flags |= MSG_FOLDER_FLAG_QUEUE;
 #if 0
 		// the logic for this has been moved into