[Bloody Sam Roberts]

I use two good spam filters but the stuff keeps coming in carloads.

Use Mailwasher. You can view email while it is on your ISP's server and bounce the spam back to the source before it is even downloaded by your email client to your PC.

That tactic alone will wind up reducing the amount of spam generated by repeat sources. What happens is the source mailer eventually gives up on your address since it receives back no indication that the mail was delivered to the destination.

[Blue Screen of Death]

The problem with mailwasher is that most spammers do not have a legit return path address. The bounce does little or no good.

[Mitchell]

bounce the spam back to the source

No, don't do that! You're just adding to the problem.

The reply addresses for both spam and e-mail viruses are virtually always bogus. You're just sending unsolicited e-mail, aka spam, to somebody who had nothing to do with the mail you received.

The idiots who built these bounce options into their spam filters have made the spam problem significantly worse. Bounces to forged addresses constitute some substantial portion of the spam out there. The same goes for viruses and the ill-conceived bounce functionality in some virus filters.