IF your talking about stripping off the anodising from the aluminium trim...I don't think the oven cleaner needs to sit on them for very long. As far as coating them after they are polished...I think it depends on how much the car is in the elements. Some people have clear coated them and others havn't done anything. If you choose to not coat them with anything, and you drive the car alot, you will probably be polishing the trim more often.