This problem has been going on since the board started up. Piotr, Mr. Poo, drpornz, maged, moblem, too many to name.

I'd suggest you keep them in check, rather than getting rid of them completely. This has worked in the past. EYD is right--they are just the village idiots, fun to take a swipe at now and then, but don't let them around the women and children too often.