Hi there, saw a process amongst the community of old school electronics nerds where they take their old 1980's computer monitor or Gameboy or Commodore or Playstation, etc and they have a process to de-yellow plastics.

I figured our cars have ABS plastic too, so why not try?

I took Salon 40 (not the creme, but the liquid...it is basically high concentration hydrogen peroxide, get it at a beauty supply store) and filled a clear plastic container with it and dunked my parts in it and left it in the sun for 2 to 3 hours at a time. My parts were a W124 "mushroom" or "parchment" color. I used clamps to pinch each part to weigh it down to sink it otherwise they'll bob and you'll have blotches at any parts that are allowed to dry and heat up in the sun where the peroxide had touched that spot. You must keep them submerged!

See pictures and video below. The 1 "before" part is on the right, and the 2 "after" parts are on the left. I took it with flash on and flash off. They came from the same car.
I think it turned out amazing, and they match the interior perfectly now, and I heard it works best on light colors and shouldn't be used for dark as it can make it blotchy. You can also use the "creme" version of the product (red label instead of blue) but I heard you have to cover it with saran wrap and if it's too thick in one area it can make it blotchy too.

The interior drove me nuts before this as the leather or MB Tex would be a non faded color, and only certain things like the plastic covers on the side of the seat, or the flip down mirror on the visor, the ash trays doors on the rear doors, etc were discolored unlike the rest of the interior and just made it look old.

I also have researched and found out that it will turn yellow again, however I have permanently sealed it from this problem by using 1K automotive clearcoat since most have UV inhibitors in them. Since those usually come in gloss only, what I do is spray it VERY far away from the part (like 5 feet) and let it mist on the part to cover it so it is a textured "matte". I can then follow up very lightly with a scotchbrite pad and it dulls it bad to where it looks good. I know they have like Rustoleum "Matte" automotive clear paint but it's Rustoleum...and ...just....no.

If you guys start trying this and are pleased, how do we sticky this as a Mercedes forum in general, in the main main section, rather than me posting this in each W chassis forum?

And yes, I know, you can just paint the plastic parts but unless you can find an automotive paint shop that'll 1) match it correctly to begin with and 2) put it in a can for you in satin, or you have a compressor with a sprayer, etc, this hydrogen peroxide method is just slightly easier.
FINAL WORD OF CAUTION, THIS PEROXIDE IS NASTY STUFF, ONLY HANDLE PARTS WITH GLOVES OR YOU WILL GET CHEMICAL BURNS ON YOUR SKIN, ALSO COVER YOUR EYES. I CAN'T EMPHASIZE THIS ENOUGH. (you can get 3% hydrogen peroxide at the store but it'll take much much longer in the sun, perhaps 8 hours a day for several days, etc. It is up to you). I also put the rubbermaid container's lid back on to store the stuff so I can reuse it.

For those of you that want to read more, just go on Youtube and look up "retrobrite" or "deyellow plastic" and there are tons of links on there. it's strange to me that I don't see this amongst car enthusiast communities. Maybe they just match theirs and paint the plastic instead, but is it really truly matched?

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