I've used it a couple times, I never had anywhere near the luck some seem to have. I put all the right ingredients in there and throw it out into the sun but I've never experienced it turning anything into "like new". Perhaps I did it in the Michigan spring/fall and didn't get enough light to it... Whatever the reason I've been reluctant to screw with it since.
Honestly all of us, as consumers, need to stand up and say enough with this shitty plastic! ABS is crap plastic, and it's just ridiculous that anything kept in nice condition can turn from white to yellow. In some applications it's damn dangerous! Car headlights were once a nice and wonderful glass, good luck changing the color with age! Now, you get a car that's 5 years old and the damn plastic headlights have not only yellowed but they've fogged up and are stained. There's less visibility to the driver and it's harder to notice for other drivers. How car companies (all of them) can get away with shit is mind blowing. I'm wondering if the special fluids they have to get rid of the headlight haze would help with other ABS plastics?
This is not an issue with plastic, this an issue with this specific type of plastic purely used by companies to save money. Screw the companies who probably saved 2 cents a unit by using ABS but the people are to blame as well... We need to stand up and scream we're not going to buy this shit anymore.
The only reason I mixed up some retro-bright was because of my "new" Amiga hard drive I got from Ebay. Just this yellow piece of puke when I got it. Now my Amiga500 it's very hard for me to really tell... It's just been so slow in yellowing the only thing that makes me wonder is by looking at pictures online... But then again my 500 comes out looking whiter than I see it when I take a picture... I'm pretty sure it used to be more white but again, it's been so slow and it's only the slightest change at this point. I attribute this to two things... 1: It was in the basement for most it's life, no sunlight got to it. 2: Lights in the basement were standard incandescent/tungsten. People like to blame smoking environments for increased yellowing, I'd bet real money that any major yellowing was the cause of heavy sunslight/florescent light exposure or high humidity levels in an attic. Time after time, when I find something sitting in an office with those damn ugly pulsating mercury filled POS florescent lights I find white plastic that has turned yellow in no time flat.
So this hard drive I got worked great but looked damn ugly... I tried it... Not only on the hard drive but I put it on the Amiga and all sorts of things... Even the C64 which I'm positive looks exactly the same as it first did... It did seem to wash off the puke stains from the hard drive but it's still damn yellow and it's my number one complaint with hooking it up to my 500... It's just butt ugly next to it.
Now I can't say the plastic feels any more brittle, though I wouldn't be surprised if there were side effects... After all, even the people who've had great success say it all came back in 2 years... It's obviously screwing with something rather than fixing the problem... And if you want to truly fix the problem? Screw the original plastic and pick out a similar paint. Take off any stickers and do what Commodore should have done in the first place, paint the damn thing! I will be researching a good paint to use for my hard drive, I'll see how that turns out before thinking about the Amiga. But if you plan on keeping your Amiga and you want it to look nice, then you really should just paint it and be done with the plastic. And if it's just collecting dust as a collectors item awaiting a future high bid, then as with any old shit you'd best be reminded nobody buying it wants you to fuck with it. They don't want it painted, they don't want it retro-brighted, old crap keeps its greatest value when it has not been touched. Don't be surprised if people can figure out a way to tell if that thing has been screwed with via retro-bright, and watch the value plummet. So if you want it to look nice for yourself, find a nice white/beige plastic paint and make it a project, should last forever... The only trouble would come from those damn keys... hmmm... It's really too bad Commodore couldn't have made it with quality plastic that didn't yellow...
My SNES had some yellowing problems, that was all Nintendo using the crappy plastic on certain parts from certain years... Mine was just on the game port area, nothing else... I came across a free SNES which had terrible yellowing on the rest of it but the gameports were perfect! So I switched them over. I noticed the spacebar getting a little yellow on the Amiga and simply replaced it with another one. There may be those replacement options. But I"m with the guy writing the article, it sounded like snake oil from day one, I only tried it because of what all these YouTubers said, and... I guess I couldn't do it right or it's only good in the summer around here... I still have everything for it but damn if I'm going to take all that crap apart just to get the results I got from it. If I ever take it apart again it's going to be to paint it!