Rubber Rejuvenator. It's used to clean and restore hardened rubber rollers in printing equipment. Works great on many plastic surfaces (ever try taking permanent marker off of a dry erase board? This does it!).
I've used it to clean many computers.. The plastic bezels and the painted metal surfaces.
Find it at local printing supply shops (Xpedx)
Of course there's everyone's favorite... Mr. Sheen! :lol: