You can't delete anything without the EDIT button on them, and only answers should be available, if you are talking more than a few minutes ago.

The older ones you can change them the way you would answer them now, or you could edit them and put "Flag this answer, please". Or use feedback and ask the staff to remove them.

OR, you could edit them, leave them the way they are, and add something like "[EDIT] I was young and dumb when I answered this. Today my answer would be..." and answer it.

You can only edit items that still have the "edit" button on them. Another option is to flag the items as "nonsense" or "offensive". The mods will review the flags and remove those they agree are nonsense or offensive.

You can also click on the "feedback" link at the bottom of the page and ask Admin to help you out. Explain the problem and provide them with links to some of the content you are concerned about.

You can't delete questions or comments, but you can remove your answers and leave "flag this answer" or "delete" in their place. If a question or comment really, really bothers you, you can contact administration and they may be able to help.