If your reference to Sally H2O2 cream was the stuff I used (ie: hair bleaching/coloring products), don't do it ! It messes with blue and black plastic, to the point of it not being blue or black anymore. Its use was an experiment gone wrong. We now know better because of it, and the Xanthan gum mixture is the preferred route.
Several people have commented on the Sally H2O2 cream as being bad for dark plastic. I can't comment on that because I haven't tried it on that, but I have to say it works GANGBUSTERS on the Apple biege plastic. A little goes a long way. I bought a quart back in April, have done (perhaps) six or seven batches of parts and still have most of it left. It is still quite effective, too. Which leads me to my purpose for posting.
Yesterday I decided to clean up a batch of Apple cases (monitor, IIGS case, and about six disk drives). Heretofore I have been doing them indoors using a Sun lamp (big spotlight with high UV penetration). I've been pleased with the spotlight in general, which will restore a side in somewhere about five to six hours. I use the Sally cream with a 'glug' of Oxibright (mine came in liquid form).
Being as we are having beautiful summer days here in Michigan (USA), I decided to take advantage of the sunlight, out of doors.
WOW!
I set up the first batch with their first surfaces aimed at the sun (covered with plastic film to prevent drying) and took a break for some lunch. Glancing out the window, it seemed the parts were quite lightened, but thought it must be the angle or the whiteness of the gel or something. Went out a bit later and THAT SIDE WAS DONE! Continued on to the next side (for generally cubic shapes, it seems like I need five exposures). I quickly found that I could effectively treat each side with about one half of an hour of exposure. It was well done, too! (Well done, not well-done, if my meaning is clear.)
By mid afternoon, everything I had prepped was complete. I'm coming down the homestretch now on a second batch for today.
Two things; I am amazed at how much more powerful the sun is than that apparently-strong sun lamp, and also that my outdoors results seem so much quicker that what others have reported.
I'll invite comments and questions.
Rich