Comment spam is obnoxious, but the spam filters are nearly so. Just when I thought it was working well, I noticed that Joe Huffman had a comment stuck in the filter.  One in 166 isn’t bad, I suppose, but I still have to scan through all my spam like I did with my previous manual method.
We should just be allowed to flog spammers publicly.
Maybe you should just required every commenter to put “#notspam#” in their comments, then auto-block any comment without it.