Cleaning old yellowed Apple components

Here are some purported solutions (Google is your friend):
http://www.vintagecomputing.com/index.php/archives/189
http://uk.answers.yahoo.com/question/index?qid=20060719130110AAz1qdA
http://jledger.proboards19.com/index.cgi?board=retrobits&action=display&thread=1143862731

The first link you listed was quite interesting and answered a few question I had been thinking about. Very good info...thanks.

Now I am sure my wife as some magic erasers under the sink....

Well IIc are white. Not platinium Like IIC+, and IIgs. I have tried quite a few things. I tried sandblatsing, D&L on it in a microwave. The only thing that kind of works is tooth paste with Bar Keeper helper mixed in to for a little more abrasion. This will take off a litght layer of plastic, It will then seem to light up the item as well as smelling minty fresh. Too much of this will remove all the rough surface. The splater paint effect. If done long enough it will make so smooth that the plastic will shine. Just a warning to those that think more is better. Not in this case.

Take Care

I have posted previously here on apple fritter about yellowing. I got the idea from a site about restoring piano keys and it turned out to work on my apples and some other stuff.

I used plain old Hydrogen Peroxide of the 3% variety. The piano restorer used something like 30% that might be faster however it is much harder to come by.

I put a thin coating of the peroxide on the case and expose to UV either by black light or strong sunlight. It will take several applications to get the color back. When I did mine it took an average of about an hour and a half. It has to be wet to work and too much exposure after drying especially with blacklight will cause the yellowing to come back. I generally used either cheese cloth or a single ply of kleenex paper to keep the fluid on the case.

The procedure has worked for Apple IIgs, monitor cases, external drives, IIc, mice, and my HP LaserJet 4+.
In the case of the monitor it was yellowed due to heat.
In the case of mice, I just completely submerged the case of the mouse in hydrogen peroxide after removing the internals (as I did with everything else). And just left exposed to the blacklight overnight. I put platic wrap over the container of peroxide to keep it from evaporating.

If you get used equipment and it has sharpy marking on it you can use hair spray to remove most of the sharpy from the case. I've also used dry erase markers to remove sharpy to varying degrees.

read my previous post for more information. http://www.applefritter.com/node/18172

The response to your post seems to indicate that light isn't necessary for the reaction (and may in fact be undesirable). Would it make sense to just leave yellowed plastic in a bath of Hydrogen Peroxide in a dark closet, maybe in a plastic bag?

Your right about the other post about using light. I've never tried it without light. It might work, may take longer but possibly safer. You could give it a try and let everyone know how it worked. I did not post until after I had already done all my computers & peripherals, so had no reason to try it without light. If you do it without light, I would use an airtight container to try to maintain the concentration of H2O2.

Over the pasr 25 years, I've used bleach (50/50)
and water to clean all of my computer gear. Even
some badly weathered and smoke-encrusted gear and
never had a problem with plastics or other case
materials "melting". I even clean my keyboards
this way. I use an old terrycloth washcloth and
wet it and wring it out and wipe the item and let
it air dry.

Did this a recently as last week to prep my area
for a public show. It also keeps germs down during
the winter season. Fist used this when I was working
to clean/restore some older gear that I had to put
back in service at my workspace (zero budget and
GREAT access to excess/surplus gear!).

You DO want to be careful about not getting any
actual solution/liquids into areas such as under
keys and into switches as corrosion can set in.

Clean your screens with "Windex" (ammonia/water)and
a clean, lintless cloth such as an old cotton under
shirt. Don't use any commercial "cleaners" as HERE
is where you can run into problems with screen
coatings.

Amonia kills screens.. only a few Apple models didn't have a coating or polarizer on the screen and amonia destroys them. the amount of Apple 17" CRT out there with gapping holes in them due to people cleaning with amonia!!

It is extremely damaging to LCD's too.

I use isopropyl on screens as per Apple's recommendation and toothpaste to restore my collection machines.

Be wary not to use to much paste, its abrasive and the idea is to just knock of a fraction of a fraction from the top when cleaning - ie leaving the finish on the plastic

I will be trying Hydrogen Peroxide at around 20-30% With UV light to bleach them back. They do this ivory keys and some plastics. Wanting to test it out to see how well it works. Hard part is getting a STABLE Hydrogen Peroxide @ 30%. Not cheap, and will not last.

Take Care