How to delete replies

when you're logged in, when you look at a post (topic or reply) there is a 'delete topic' and 'spam' link exposed to admins and mods that you can click.  They are gray, at the top right of a post.

yes, I know it.
But when viewing the topic, u still can notice how many relies that topic has had though the replies r not visible.

you can use this hack:
http://support.lefora.com/2009/06/15/removing-the-hiddendeleted-marker/page1/#post13796637