I've said this before and it's certainly worth highlighting again after watching this video here. The 8-Bit Guy YouTube channel is one of the best out there if you're interested in vintage technology and gadgets and how they work.
A few of his videos center around Apple products from yesteryear such as this Apple IIc he picked up. Now, if you're not an Apple fanboy you might be asking why you would care about this video. Well, it's because the video is really less about the Apple IIc and more about the incredible process he went through to turn that iconic '80s and '90s beige exterior (which has yellowed over time) back into a shining like-new shell!
Apparently, the magic is hydrogen peroxide and some sunbathing.
He has one more video about the process here.