There's a new app available on Android that does this called Exfoliate. It exhaustively goes through all your friend's walls and deletes posts, comments, and likes.
Yes. I looked through Facebook help center and settings, and could not find anything regarding disabling comments from friends. There is however, an option to disable comments from subscribers and from friends of friends on public posts.
Best Answer
Simply type
8-)
or8)
orB-)
orB)
in your comment.Here are some links for more smiley emoticons: