I have a couple of spots on my rear bumper in the center about 12 inches apart below the rubber strip that are about the size of a dime where it just looks like the finish is off. I don't think the spots are pit marks. The rest of the bumper is in perfect condition. I bought the car brand new in 74 and it has never been driven in the winter. Any and all suggestions would greatly be appreciated. Thanks to all in advance.