dnt remove the strips as you'll have a flat lip along the car and it'll look shite. If they are not painted, paint them. This is wot i'm going to do in the summer along with the bumpers
providing they haven't got deep scrapes down,just clean them with terps or brake cleaner, then prime and spray them. dont use sand paper because it'll screw the finish of the bumpers and mouldings. They'll look fine, i assure you