If it's nicotine, then Krud Kutter will remove it, but be careful, as it eats any latex based paint (usually the white coating behind plastics, marquess, backglasses), but a quick swipe over with instant rinse is usually safe. (Test with a dark cloth).
However, this likely isn't nicotine, but rather bromine (from flame retardants) or something else in the plastic that reacted to UV. In which case you can try to do a Retr0brite treatment on it and it MAY work.
http://retr0bright.wikispaces.com/