Toss them.
If you want comments on your own blog you can make them yourself. Most of the spam comments go to websites you do not want to be linked to. One of the ways Google rates a Blog is how well you control spam in your comments.
Google will not knock down your rating for ugly sites linking to you but anything going from your site to a Bad site will be held against you because you can control it. --Control is a wonderful thing isn't it Mikey?--- You are rated by the companies that keep (you link to).
You can make comments and link them to this forum, any of your friends websites. You only want your links going to family friendly websites. I have over thirty sites you can link to anytime you want---lol---
Delete all comments that you do not know are going to safe websites. You can put a Captcha in there so it has to be a human to even leave a comment. Turn on Akismet from Wordpress and most of the automated spam will be eliminated.
Rick the SEO guy---Carpet cleaning is my hobby---I make my living with SEO...