Everything Else

I'm trying it on some yellowed Mac pieces right now. I don't think I have any yellowed SGI stuff. We need the magic formula that gets rid of white marks/scratches.

For the white marks/scratches use Bar Keepers Friend. That's what I use and it works great.

In my experience, the best way to remove light scratches and scuffs from colored skins is via careful scrubbing with an ordinary rubber pencil eraser. The large block-shaped kind is easy to hold and can be applied with reasonable accuracy. You should be careful to scrub directly over the mark, and don't overdo it, since excessive scrubbing will wear down the plastic texture, leaving a shiny spot on the case. However, for most light scratches, this method works almost perfectly.

Have not tried Mr. Clean Magic Eraser - sounds like a similar process/result?

Yes. Perhaps better even. I think the pencil eraser leaves leftover gunk all over that is a bit more difficult to cleanup. The magic eraser leaves water behind that wipes up easily with a towel. I can't imagine that it is possible to overdue it with the magic eraser, either. Really, they're magic.

I'll have to try that, I've been looking for new-logo green Octane skins for a long time with no luck but I might be able to get a set that's not too bad.

Back to the deyellowing . I've now read through almost four threads on the topic here. And I'm using what seems to be the best method so here's some condensed info for those who don't want to read hundreds of posts.

I've got a beige Mac drive bezel in a 3% v/v hydrogen peroxide (the kind you can find in any drug store) bath with a bit of Oxy Clean powder and an incandescent 60W black light. Foaming started after about 30 minutes and I've left it overnight with some success but its going slow. The peroxide concentration is on the low side but people have reported success with even lower. I think the bigger problem is the black light. Fluorescent tubes seem better but I haven't found any for a decent price yet. The typical incandescents seem to be just coated on the inside to let only UV through and don't work too well - I found out after buying it.

I have a few more small pieces to do and then I need to switch to the paste method with is the same solution and some thickening agent. It looks like xanthan gum, arrowroot and corn starch have been used so far - nobody seems to have tried readily available flour. I also want to see if I can come up with a more gel-like version.

Then there's the much more involved idea of making some crude version of the vaporous hydrogen peroxide generator we just got at work for whole-room decontaminations.

What do you think it would do to colored plastics, like the dark purple of an Indigo2?

Are you talking about them being yellowed? I did have a granite keyboard that was yellowed but I don't any more so I can't test any SGI stuff.

I ran out last night and picked up a better UV bulb. By this morning I had another bezel done. Pic in a bit provided I can take a decent one.

EDIT: Here's a Mac definitely worth treatment. The floppy bezel and blank bezel were done. It really wasn't that bad to start with but looks new now.

I have a teal and purple Indigo² that have a yellow tent to them. They have some labels removed, and you can tell the nice original color they used to be.

I would like to take the yellow "tinge" off, but not bleach out the color.

Well, treat an extra piece of something even if its not yellowed and see what happens. I don't think its going to be a problem if you keep the peroxide concentration low. Someone had used a 12% (I think) cream from a beauty supply store and it caused problems with blue and black - and possibly other colors, I don't think he tried it. I'll see if I can find something once I'm done with the Quadra.

That reminds me, those in the US can find 3, 6, and 12% hydrogen peroxide (sold as 10, 20, and 40 volume) in Sally's Beauty Supply stores. I bought the 12% in a 32 oz (946 mL, get with it US and use a system that makes sense) bottle for $4.98. I ended up dropping the concentration all the way down to 1.5% this time since I needed quite a bit more.

I have a entire teal broken top case I think I am going to try, also some yellowed granite keyboards.

I am thinking about buying one of those $20 shop lights, and put two UV bulbs in it, and place it over a big Rubbermaid container.

I also read to keep the OxyClean powder amount low. Any tips to send my way?

BTW, your parts look great!

The lights you're talking about would probably be better than the coil bulbs I bought.

The tetraacetylethylenediamine (TAED) in the OxyClean is supposedly acting as a catalyst meaning its while it aids in the reaction its not consumed. Catalysts are typically used in much smaller quantities than the reactants since the can participate in individual reactions over and over. So a gram would probably go a long way. Plus you'll have trouble dissolving all of it if you use too much.

The plastic's not alive so its out of my field but I just read the science part of the wiki and things seem off even relying on what's left of the old chemistry knowledge I don't use. They're claiming UV light releases bromine free radicals from the tetrabromobisphenol–A used as a flame retardant in the plastic. These then migrate to the surface where they bond with oxygen and produce the nasty yellowing. During the treatment the UV light destabilizes this bromine oxide as well as the hydrogen peroxide (the breakdown of which is also catalyzed by the TAED). Free hydrogen ions from the hydrogen peroxide then displace the oxygen to form hydrogen bromide and that's where the explanation ends - actually before even saying hydrogen bromide. If that's all that's going on there are much easier sources of hydrogen ions, any dilute acid solution. That's easy enough to test though I'm thinking there's more happening but what do I know.

So, I guess technically, if used in the correct amounts, it should not have any "bleaching" effect on the plastic.

If the peroxide concentration is too high you will get bleaching. Years ago I temporarily turned my finger tips white doing something with a 30% solution so yes it bleaches things.

If I were you I'd soak the part rather than use the brush-on method for your first try, especially since the situation with the colored Indigo2 is a bit different. Start with a container large enough to hold the Indigo2 top. If you place it face up there's going to be lots of empty space underneath so you might want to stick some things in there to take up space and save on hydrogen peroxide solution. Get some 12% hydrogen peroxide and dilute it; I'd go with 1% simply because it will cost less. Mix in the OxyClean, submerge the Indigo2 top, and hit it with the blacklight. Do it when you have time to check on it every few hours. It took at least 8 hours for my parts to change and that was in 3%, they weren't all that yellowed, and I probably could let them go even a bit longer. So don't be surprised if it takes a day or so.

That sounds great! But, I might need help with my delusion math.

Also, I hope Home Depot/Lowes has full sized UV florescent tubes.

Just to give you an idea of what I am talking about...

Here is the old Indigo2 case, with a brand new, just pulled from the plastic, faceplate. Assuming it is not a variance in the plastic because of a different batch, the case has a definite yellow "tinge" to it making it appear darker. The pic really doesn't do it justice, it is a BIG difference. It makes the case look old and tired.

I went to Lowes and got some supplies today. I could not find anything large enough to set the Indigo case flat, so it looks like upright is my only option. I can also monitor the change better by only submerging half the case at a time. I plan on lining the inside with foil to reflect the light every way. These same lights will take the plant type UV bulb, I wonder how that would do? If it would be too intense?

Have you considered trying with natural sunlight first? might be easier to get the whitening to happen more evenly?

Sunlight supposedly works better since you get a lot more UV but if I put anything outside right now it would first freeze then be covered by 18" of snow.

The only upside to that is I should have a day off tomorrow to play around with this.

If I want more "intense" UV rays, I can just upgrade the light bulbs to the type that are used to grow plants.

With a colored piece like this, it is all about slow, steady, and controlled environment...

I heard about this awhile ago on classiccomp, I think that once I get around to doing this I will actually be using an indy lid that I replaced because it was scuffed and discolored, and I have an indigo case and octane front panel as well that have been replaced...

The countdown has begun!

49 liters of water, to 1 liter of 50% Hydrogen Peroxide, and one scoop of OxyClean.