deleting unwanted posts?

For future reference, how do you delete unwanted posts made by yourself or others on the message boards? However I heard somewhere that the posts can be deletable if you used a password, and I did'nt put a password in my posts, and it said that on this site passwords are for admins only. Is this true? If you ever fix the message boards you should at least try to have a feature that unwanted or harmful posts can be deleted through time if the posts is'nt BUMPed. It's only a suggestion.

And BTW I was talking about the Text Boards, not the Image Boards.