Plastic light fittings on ceiling back to white help?

Is there anything i can do to bring the fitting back to white? I've just moved into a new home and all the fittings are yellow with either smoke or age and i've tried scrubbing them with every kind of cleaner i know. Is there something i can put on them to bring them back to white? I didn't want to put gloss paint on them as this will turn yellow too!