whiten yellowing plastic

[DYNAGOD]

Does anyone know any magic tricks to help whiten yellowed white plastic?
Ive read that bleach actually yellows plastic so i dont want to go there.
is the yellowing only surface deep or does the entire substrate turn yellow throughout with age.
thanks all!

[whammoed]

I have a white outdoor plastic clock that turns yellow from the sun and weather.  It is only surface discoloration.  I have buffed it out with rubbing compound.  Plastic polish would probably be better if you are worried about leaving scratches behind.

[DYNAGOD]

thought novus might work, was curious if there was any secret tribal knowledge thing like ,i dont know, vinegar or some other odd thing that might work without buying anything.

[whammoed]

Well, if its really light superficial staining, car wax/polish will take it out.  Most people have that in their garage.

[rchadd]

toothpaste?

[Geekboy]

I have an old intercom system throughout my house.  It is white plastic that had yellowed.  I just got some white Krylon Fusion spray paint.  It worked like a charm.  Intercoms look brand new.