That's the problem---they don't delete!
I remember from the past it was something to do with having Adobe ( or something) box checked. Well mine is and obviously cookies is ticked.
Prefer not to delete all cookies for obvious reasons.
Your suggestion didn't work unfortunately, but when running the cleaner just now I had a pop up saying to close browser as cookies wont be deleted.
Never had that before, but still no success.
XPHome SP3 and FF8 by the way,
I think you need to close FF to clear the internet cache. I've just run Ccleaner with FF open then back to the Cookies list and some still show, so closed Ccleaner and re-opened and the left hand column is clear until a page is refreshed or another tab opened. If your list doesn't budge then I go with rawprawn and try a fresh install of Ccleaner.