Easy List Cleaner
http://www.coralpalms.com/software/easy-list-cleaner.html

No More Duplicate Mailings - Stops any chance of subscribers getting duplicate mailings when ever you send to your list. Cleans Any List In Seconds - So simple to use that all you have to do is paste your list in a box, click a button and the software does the rest...on ANY list! Helps To Build Trust - Your subscribers will never receive double mailings again once you start using the software while other list owners are still sending to list with duplicates out the whim-wham.