Option 1: Try it yourself: Visit the item using the browser that created it. There will be a "Delete" button at the top.
Option 2: Wait it out: At the bottom of the page it says when the item will be deleted. That will happen automatically and is permanent.
Option 3: Special request: If you have a special case not covered by the above, submit a support ticket requesting deletion and explaining the reason (e.g. leaked secrets or TOS violation).