Suppose I have one post on my site: http://vsagar.com/2011/11/30/what-is-a-breadboard-how-we-can-use-it-to-construct-hobby-circuits/
This post has 54 comments and now after around 6 months I found that number of comments on this post are just like spam.
That time when I was a beginner, I enthusiastically approved all the comments that I received.
But now I want to delete all these comments. Right now this is not possible in WP.
So there should be some solution on this problem.