This was mentioned on Facebook recently as a possible way to get the yellow out of vinyl doll bodies. I haven't tried it but I plan to. Click on the logo below or the title of the article to go to the original post.
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How to deal with the “not-so-mellow yellow” of old computers and consoles
Anyone
who has dug their old computer or console out of the cupboard or loft
for some retro gaming will probably have noticed that it maybe hasn’t
worn too well with the test of time. The plastics these machines were
made of is called ABS and to make it flame retardant (just in case it
catches fire after a marathon session) the plastics manufacturers added
chemicals that caused the plastic turn yellow or, even worse, brown over
a long period of time.
It was originally thought that the yellowing was permanent and that the
only solution to this was to paint the plastic in its original colour
and cover the problem up. However, a chance discovery was made in March
2008, by The CBM Museum at Wuppertal in Germany (http://www.forum64.de),
that immersing parts in a solution of Hydrogen Peroxide for a few days
could partially reverse the process. This was initially taken up by the
Amiga community in Germany (http://www.a1k.org) and the idea eventually found its way to the English Amiga Board (http://eab.abime.net),
where a madcap collection of chemists, plastics engineers and retro
hackers managed to perfect this concept and put it on steroids, with
help from other forums.
Dave Stevenson from Manchester, UK, aka 'Merlin', the chemist behind the
project, explains. “I came across the use of peroxide in July 2008 when
Kristian95 told us over at EAB about what people like AmigaGTI were
doing with it over at a1k.org. I was intrigued by this, as I am a former
industrial chemist. I am also a plant Safety Manager by trade and,
purely by coincidence, around that time I read about a dust explosion
that had occurred in the UK with a chemical called TAED, which is the
booster in the ‘active oxygen’ laundry products.”
“This got me thinking, and after some really 'full-on', serious
chemistry discussions with other EAB members, like Rkauer in Brazil, who
is a plastics Engineer and my good friend Zetr0 from Kings Lynn,
Norfolk, UK, who endured endless phone calls from me, we wrote some epic
threads on English Amiga Board about the possible causes of the
yellowing and eventually we arrived at the theory that it was the
Bromine in the flame retardant that was the cause. We also knew that
Ultra Violet light was another major factor. Having identified the
culprit, the next stage was to try to develop and perfect a means of
treating the plastic and reversing the yellowing quicker, without
causing damage to the plastic. Being a former industrial chemist helped
me tremendously, in understanding what was going on at the molecular
level and to develop a treatment process to reverse the effect.”
“The problem was finally cracked in late July 2008 with a mixture of
hydrogen peroxide, a small amount of an “Oxy” laundry booster as a
catalyst and a UV lamp; we believed that this could do the job in hours
instead of days. Proof of this concept was demonstrated on EAB by
Tonyyeb from Hull, UK, Chiark from Leeds, UK and myself. The original
test I did as proof of concept took two hours, as opposed to up to the
five days it took for the original tests at CBM and a1k.org. We were on
to something!!
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You don’t have to be a smoker to know the pain of yellowing hardware.
Any beige box of a certain age starts to darken and stain like an
Englishman’s teeth, turning beautiful retro hardware into the equivalent
of a filthy, leering uncle, something to hide, not flaunt.
The reason? Retards. The ABS used for these old machines was rendered
flame-retardant with chemical treatments. These chemicals are the ones
which cause this unsightly yellowing and until now the only fix was an
equally ugly coat of paint.
Retr0bright to the rescue! In a twisting story that started with
German boffins and English Amiga nerds, it was eventually discovered
that bromine was the yellowing agent, and UV light didn’t help either.
The McGyver-esque answer is a mixture of hydrogen peroxide and a dash of
commercial laundry booster "Oxy". Paint this on, stick the old computer
out in the sun (or under a UV lamp) and several hours later you have a
shiny white machine.
The folks at the Retr0bright project will sell you a gel, but if you
actually own old hardware then its likely you’re a tinkerer already, in
which case you can make your own. Full instructions are on the
Retr0bright wiki, but the short recipe is this: Take a weak (10%)
solution of hydrogen peroxide, add a dash of Oxy, apply and leave in the
sun for an afternoon. That’s it.
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