A spam filter with built-in challenge-response system
Pros & Cons:
xTerminator is an alternative which works in much the same way as MailWasher, and is totally free.
I must say, though, that I prefer MailWasher's user interface. It uses a built-in Challenge-Response System that allows you to send people a question, which if correctly answered, will provide them with a password. In the future, their messages will not be deleted again or can be automatically added to a Friendly Content list.
Unfortunately this program is no longer supported by the developer, but the program can be downloaded from other websites.
xTerminator was reviewed by Gizmos Freeware on