Wheel fitting new rotors and pads I removed my calipers and gave them a good cleaning. Like yours, they had dull spots. After cleaning of all the grease and dirt, I used lacquer thinner and removed the decals and replaced them with new ones, then sprayed them with high temp clear coat, let them sit in Florida noon day sun for about an hour. Now they look new again. On the fender wells you could use Bumper Black or use the undercoating spray in a can.