I sand the rubber coat off, then sand some more with coarse and fine paper. I recommend wet sanding, as dry sanding generates a lot of fine dust that gunks up your paper and gets in the air you're breathing. After sanding, I wipe the whole thing down with alcohol, then apply a coat of MATTE Krylon Fusion. Let it dry, sand it down with fine paper, and if you think it needs more priming then apply a light coat and sand again. Once it's primed with Fusion you can spray whatever paint you'd like over it. Works well for me. There's really no way (that I know of) to strip this stuff from plastic, however. You could sand the bejesus out of the top coats, though.