I use Akismet, the spam blocker WordPress offers, and it’s an excellent tool. I get so much spam I don’t know what I’d do without it.
You have the option of setting it up to either automatically delete all spam so you do nothing, or to send it to a special “spam folder” for later review/deletion.
I opted for the second, because sometimes Akismet makes mistakes. I have had legitimate comments wind up in my spam folder, as well as spam that somehow never got flagged as spam and wound up in my regular comments folder waiting to be approved.
Legitimate comments that wind up as “spam” usually contain links–I think the limit is two. If your comment includes more than two links, Akismet thinks it’s spam and I have to manually unspam it. But for some reason, one lady’s comments always go to my spam folder even though they contain no links at all!
It’s a pain having to manually go through my spam messages every day because sometimes there are hundreds, but it would be worse to have legitimate comments automatically deleted so I’ll continue to manually review all spam before I send it to the Trash.
