Just thought someone might find this useful.
Instead of downloading all the spam then deleting it, you can delete it off your server, and if you're feeling particularly frisky, you can "bounce" spam back to the sender so hopefully they think it's an invalid email addy.
I know this can be done other ways, but I'm too stoopid to figure them out, so this thing rocked for me.
http://www.mailwasher.net/
And no, I'm not getting paid and I'm not affiliated with this thing in anyway. Just thought it was useful. Actually, I came on my keyboard a couple of times when I was using it I liked it so much.
P.S. It's pity-ware. Free if you want, donate if you want.