If I remember correctly, the peroxide method is called "Retr0Bright" (number 0 in the name). You can google it. They use it to lighten old computer parts to make them like new and it removes the yellowing with some chemicals that mix into a gel, you paint it on and put some sun lamps or direct sun on it for periods of time, clean off and repeat. We bought all of the ingredients but decided to use TileDoc and epoxy the bath surfaces instead.
We will be using the Retr0Bright mix on the widnow openers and will post here the results. There is also a post on here somewhere of the Retr0Bright being used on AS plastic parts with good results.
Tadd, Beth, Grundgetta and Weeble
Proud to be Air #37137