There is no option to delete your comment on any cf post. Generally there's no problem because it forces you to think before commenting and prevent any immature comment. But problem occurs when someone edit there blog totally and now your comment not only seems to weird but also stupid on that blog. Though you can edit your comment but sometimes you find nothing relevant to say on that new topic.

So I want to say that if writer of a blog edit his/her blog then there should be a option to delete comment for all who comment before editing that blog.