Within a museum context, where showing original factory condition is
probably a desirable thing, have there been any studies to ensure that
retrobright (or other treatments) don't cause any damage to the plastics
(e.g. making the surface less resistant to scratches, or the plastic more
brittle, say)?
As somebody who doesn't care too much about the appearance or colour
of the machines in my collection, the only reason I would try to de-yellow
something is if it prevented further deterioration of the plastic (not the colour,
but the fact that some plastics turn very brittle with age, for example).
I do not believe retrobrite does this (does it?)
I don't know of a treatment that does, is there one?
Personally I quite like the patina of a yellowed machine anyway - being
able to see how it sat in a room, or where stickers used to be and such;
it's a minor thing, but sometimes it does tell a little bit of a story.
Maybe in 20 years if I ever sell any of my collection I might consider it,
but for now they may as well stay yellow :)
I'm leaving mine alone (and not just because I am lazy). It would appear you
can use retrobrite at any time, but you can't undo the effects of it. So I'll
keep my machines as they are (unless there is some treatment to
prolong the life of the plastic), if some future owner wants to deyellow them
after I am in a pine box, they can.
-tony