If you are an Advanced User who has priviledges to edit Registry here you go.

Method 1:

          Close Visual Studio (if its open)
Start > Run > RegEdit

(Backup registry before making changes)

GOTO

HKEY_CURRENT_USER\Software\Microsoft\VisualStudio\<version>\ProjectMRUList

remove unnecessary items from list.

If needed reorder your list.  File1, File2 etc. Otherwise Visual Studio might not read them properly.

Similarly repeat the steps for FileMRuList
Method 2:

If you can’t edit registry or not feeling comfortable here is an alternate method.

http://www.codeproject.com/csharp/VSRecentcleaner.asp

Happy Programming