You can't delete your own. You can edit them though. :P

Why would you want to delete your posts anyways?

Well, you could always ask a minimod of the section to lock it via comments. :P

You can't do that on every forum, but okay. That's fine for you to think it's stupid.

You can delete your own comments.

The link to do that is at the top of your comments page.

If you want to delete comments you make to other users just do the 'Profile to Profile' and the option to delete the comments individually will be there.