persistent deleted custom fields
Using Jamroom
That doesn't really make sense - if they are still showing then they are either still in the database, or for some reason are still in some form sessions. In your "reset caches" check the "Reset Form Sessions" option and see if that helps. If they STILL show, then they have not been deleted OR they were not deleted from the right form. Remember that most forms have BOTH a "create" and an "update" form - you'll need to remove the field from both.
Let me know if that helps.