Long story short: BAD IDEA, don’t.

It’s widely recommended to edit some of the spam comments -removing the spam url and editing comment content to something more related- and approving them in order to gain you some SEO advantage.It’s supposed to give you SEO advantage if your article has more comments (You could fake it by typing in / creating comments yourself but it would not be from different IP’s)

I did not like this idea at all but wanted to give it a shot just to see what happens. And turns out when you approve a spam comment, the spammers only get more aggresive.

Bottomline: If you are willing to “supposedly” gain a little SEO advantage by converting spam comments into actual ones, get ready for even more spam action.