Comment Spam

Comment spam is the most annoying thing about blogging. I've was going to try MTCloseComments, but that only works on SQL-hosted blogs, and mine is currently sleepycat. Anyone know of a similar solution that works on sleepycat-hosted MT blogs? (I'll move everything over to Postgres if I have to, but I don't want to.)

UPDATE: Actually, converting everything to Postgres was not difficult - though it was time consuming - because SixApart has a script for the purpose. I had to delete the IP ban lists from all of our blogs, and also the activity log. I've installed MTCloseComments, but it won't take effect for another week because now all of the posts are newly modified (as a side-effect of being moved to the new db). On the other hand, this should make the site a little faster to load, too, so the time was worth it even if MTCloseComments doesn't end up doing what I want.