Scipt to delete duplicate messages in Sent and Inbox?

[Mark London]

Hi - We have a lot of users who send themselves files or message
reminders, that of course also get stored in their Sent folder.  I would
like a script that checks for such duplicate messages using the
Message-ID line, and delete the message in the Sent folder.  Has anyone
written such a script, or is there a better way to do what I want?
Thanks. - Mark