...i tend to stay away from buffing wheels because i don't have a good feel for when enough is too much
I have heard tooth polish does wonders, I have yet to try it. They say to use a clean cotton cloth and hand polish with tooth paste.
Toothpaste and toothbrush works wonder on water rings on furniture. It takes the white ring out of the wood. I'm sure if it works on your teeth it's gotta work on plastic.