You can use your favorite mail program's "Save As" or "Export" function to export the raw source of your messages into a text file. Then use eMailerX to "Bulk Remove" them.

1. Open a Bulk Remove window under the addresses menu.
2. Drag and drop your exported file on it.
3. Edit the list if you need to.
4. And finally, click to remove all occurrences from the main list.

Here's a screen shot of the Bulk Remove window.

http://www.wristondevelopment.com/BulkRemove.jpg

Cheers,
Kevin