Don't smoke next to it and certain household cleaners seem to yellow this stuff prematurely too, although I don't have any data collected to know what not to use. Stuff like Fantastic and the like - probably not a real good idea. Mild dishwashing detergent and water seems to be fine.
Oh wait... the absolutely BEST product I've ever used to clean plastics is called Novus. I use it on my pinball parts. Not only does it not scratch or yellow plastics, but after you buff it out, you're left with the super "clean" feel that's supposed to be anti-static/dust repellent.
