If you moderate a Mailman mailing list that gets lots of spam, I slightly modified an existing Greasemonkey script that might make your life easier.

In the Administrative Database, it will default all messages to discard, and discard all messages from the sender (check “Add foo@bar.com to one of these sender filters” and turn on the discard radio button).

Remember to look over the messages and make sure you aren’t removing or ignoring valid posts/users.

The Greasemonkey script is here.