On my 94 325i, there is a body colored strip under the rear bumper, and below that is a grey panel, which I assume is some kind of plastic. It wraps around to the read wheel wells. I've done a lot to work to get this car looking pretty good overall, but that grey panel had some tar and goop on it and might also be a bit faded. I was using some J-Wax Scratch Out on another part of the car, so I tried it on a bit of the grey panel, and it seemed to clean it up to look like new. When I cleaned it with the Scrath-Out, quite a bit of grey came off on the applicator, making me think that maybe it the color goes all the way through the piece and I had just polished away the top layer. Now I'm wondering whether I should wax it, or use something like Armour- All, or just leave it like is. Any suggestions?
Thanks,
David