On boards that try to stick to particular topics, posts may gather comments unrelated to the topic of the site. A recent question on SuperUser about Windows thinking a keyboard is a toaster suffered from this kind of issue. There are lots of mostly useless comments that have many upvotes because they are considered funny by the users, but they don't actually conform to the rules of commenting (be useful or add something to the post).
Although, technically speaking, they do add more hilarity to the post, but that's also funny talk.
Deleting such comments right away will probably not solve the problem immediately, as new users who haven't seen that post might still want to post their own funny comment, and the moderator will end up wiping the comments time and again, while the post is still popular.
Users could also be notified when it's perfectly fine to post these sorts of comments, to prevent it. But comments like that can be silently wiped to avoid notification, and possibly a repeated abuse.
Sometimes there isn't really any harm done, because all the problems have already been addressed and the solution is found in the main post (answer), and so the comments may be left as they are.
Are there any uniform ways to deal with "funny comments" in a non-hostile manner, yet not being a prude where they do no harm?