'Un-Yellowing' Old Bricks.

I have come into some old Classic Space and Futuron sets from the 80's, mostly complete too. :) But most of the white, grey and some of the blue pieces, (which is just about all of the pieces), have discoloured horribly. I suspect nicotine or direct, direct sunlight to be the culprit, as the larger wing sections are very, very yellow. Even some of the minifig's faces are discoloured where they faces are seen through the helmets!

Any tips on cleaning/restoring some what, to at least good enough that I can display them? I read that Hydrogen Peroxide works wonders, but is this just regular household bleach? Or is there some special plastic cleaning bleach that works better?

Has anyone had any success in getting these stains off?

Thanks.