How to restore the side mirror mounts?

I just purchased a 2011 Corolla LE. The black mirror mounts on the doors are gray with sparkles, I assume its glass fiber reinforced plastic. Maybe restore is a little too optimistic, just want make them look descent again. What do you guys suggest? I've seen suggestions to use a hot air gun to bring the plasticizer to the surface.
you can get trim restorer and use it on black trim. It will have to be done on a regular basis as it does wear off. I also heard, never tried it, that ceramic coating works good and will last much longer than the restorer.
I opted for a 50% blend of mineral oil and baby oil, already in the house. They are f*cked already, what's the harm? I put a lite coat on both. Was really slow in absorbing but overnight worked. A few days later it still looks ok, does not feel oily, the glass fibers aren't sparkling and they aren't grabbing the cloth. Will use my normal car cleaning routine and see how it holds up. This weekend will work on removing the cloudiness of the head lights.