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De-yellowing Compact Mac Plastics

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I started a discussion on de-yellowing compact Mac plastics in this thread: viewtopic.php?f=7&t=8794 which was about my adventures in reviving and restoring an eBay-purchased 512K Mac. There has been enough discussion about de-yellowing in that thread that I thought I would start a new/separate topic on the subject of de-yellowing Apple compact Mac plastics - in my case, a 512K and a 512Ke (and associated peripherals). Using Hydrogen Peroxide (H202), Water, Oxi-Clean and Sun/UV light, I have been able to reverse the yellowing effects of UV light.


My efforts stem from what I learned in this thread in the Vintage Computer forums: http://www.vintage-computer.com/vcforum/showthread.php?t=11877

Part 2 of that thread: http://www.vintage-computer.com/vcforum/showthread.php?t=12566

Part 3 of that thread: http://www.vintage-computer.com/vcforum/showthread.php?t=14369


The creator of the Vintage Computer forum thread started a Wiki on the subject of the causes of yellowing and how to de-yellow vintage computer plastics. The wiki can be found here: http://retr0bright.wikispaces.com/ The wiki is a good place to start - it explains why H202 and Oxi-Clean work together with UV light (it is not a bleaching process).


What has worked on my Apple Compact Mac Plastics:

Unlike many in the Vintage-computer forum thread, I have been using a much more diluted percentage of Hydrogen Peroxide (3% to 1% H202 as opposed to 30% to 40% H202) and seen excellent results. The Apple Compact Mac plastics do not seem to need high percentages of Hydrogen Peroxide.


Here is a picture of the items I have been using: P1000405


For my Apple Compact Mac plastics, I have found that store bought (Walgreen’s here in the US) bottles of hydrogen peroxide, which contain 3% Hydrogen Peroxide, can be mixed with water to fully submerge the plastic. I've mixed the store bought Hydrogen Peroxide with water resulting in an H202 percentage as low as approximately 1%. My H202 is less than $2 per bottle. Also try Target, Walmart of KMart for better prices.


I use a heaping tablespoon (give or take) of Oxi Clean for each gallon of water/H202 solution.


Note that contributors to the Vintage Computer Forums thread have created a paste/gel using various thickeners to lower the amount of Hydrogen Peroxide needed (H202 costs can add up) to cover/treat the surface. Also, they point out that you can substitute a UV bulb/light source for sun.


In general, with the exception of my spacebar, it takes about 6 hours in sunlight to fully remove any yellowing from my Apple Compact Mac plastics. I have been de-yellowing my Apple Compact Mac plastics in batches (each item in a clear plastic container of solution). The spacebar seems to be made of a different type of plastic and I have been placing it into each batch - which progressively removed the yellow from the spacebar. The spacebar took about 5 six-hour sessions to get to the same colour as the rest of the keys.


After cleaning, I have been wiping down the plastic with 303 Aerospace Protectant: http://www.303products.com/tech/index.cfm?fuseaction=product.display&Product_ID=428&CFID=48239433&CFTOKEN=80652972


Here are some results:


My Mouse:

Before: P1000400


After: P1000403


My HD20 Case:

Case before (you can see the footprint where the Mac used to sit on top): P1000411


Case in the solution (used clear plastic to allow max UV penetration): P1000413


Case outside in the sun (UV): P1000414


Case after: P1000421


My de-yellowed 512Ke and peripherals:

Photo series: http://www.flickr.com/photos/33624199@N08/3302578478/


Note the photo navigation to the right on Flickr - this series of photos shows the 512Ke Case/keyboard/mouse, all after H202 cleaning and 303 Protectant. Also in this series are some keyboard closeups showing an H202 treated keyboard and before/after shots of 303 protectant - to try to show the effect of the 303 treatment.


Overall Observations:

1) I have experienced no "collateral damage" thus far. That is to say, no logos, screened on labels, serial number labels or model number labels have been harmed or faded. AS you can see in the pictures, I did remove the square Apple logo from my HD20 case by popping it out of the case (push from the hole behind it - see the pictures below). On my Mac 512K cases I left the same square Apple logos on and experienced no damage - it's hard to tell if these stickers are made of aluminum or steel - if the latter, you risk oxidation. So far my square Apple logo stickers have been fine. The paper serial number label on the bottom of my mouse, HD20 and Mac 512 cases look fine (there was some absorption around the edges of the serial number labels, but it dries out). See number 9 below.


2) The insides of the HD20 case and Mac 512 cases were not effected in any way that I can see (Some have asked if the aluminium-based gray coating oxidized in any way).


3) Outside temperatures do not seem to effect things. I've done this in low 30 degree temps and high 50 degree temps - same results. The sun has been low in the sky (it's winter here in Massachusetts).


4) The percentage of H202 can be very low and still work. When I de-yellowed my Mac 512 cases, I could not find enough bottles of H202 to get the plastic wash tub/bin more than 1/3 full. I used water to fill the tub to the point where the case was fully submerged. The results were still great.


5) The Oxi Clean powder may not fully dissolve at first. It's ok, just leave it in the bottom of the container/solution - it dissolves eventually.


6) After the plastics come out of the solution and are dry, I've been using "Aerospace 303 Protectant" on them. The 303 Aerospace Protectant has a UV block. Additionally, to me the plastics seem dry and very subtly uneven in tone. Adding the 303 solution seems to enrich the plastic, even out the tone and has the nice by-product of providing some UV protection. Unlike Armorall (which can be oily and wet/shiny looking), the 303 Protectant leaves a non-slick and "more natural" finish.


7) Be careful with steel screws - they do oxidize - not badly.


8. JDW, through interactions with members of this forum, pointed out that bottled H202 is likely not just water and Hydrogen Peroxide and contains stabilizers that are not disclosed in the ingredients. See number 9.


9) WARNING DO THIS AT YOUR OWN RISK. I HIGHLY RECOMMEND TESTING THIS ON SOMETHING YOU ARE NOT AFRAID OF PERMANENTLY DAMAGING. As mentioned, I have experienced zero damage to any of my plastics, logos or labels thus far. However, there are several examples out there of permanent damage as a result of this process (my belief is that this damage stemmed from unnecessarily high concentrations of H202). An example of a damaged logo: http://farm4.static.flickr.com/3175/2976915302_c7147f084e.jpg?v=0 and an example of an over-whitened space bar (update - confirmed that the H202 concentration used on this spacebar was 32%): http://www.vintage-computer.com/vcforum/showthread.php?p=91594#post91594 (both of these examples are pulled from the Vintage Computer Forums threads).


10) YOU ARE WORKING WITH AND MIXING THINGS THAT COULD BE HARMFUL TO YOU. WEAR GLOVES AND PROTECTIVE EYE WEAR. I regularly reach into the solution with my bare hands and then rinse them after in fresh water. I've had no problems. Be smart.


In the spirit of sharing information, please also post significant new findings and share your results with the folks over at the Vintage Computer forums using the links provided above.


Let me know if you have additional questions. I will update this first post if additional information surfaces.



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I've been following your progress here and also the thread(s) on VC. Very Impressive!


I'm going to do that same thing with a bunch of Mac stuff too. I'm just waiting for some consistent sunlight and reasonable outside temps. I'm going to try using the cornstarch as has been suggested on VC. I've yet to hear about anyone actually trying it. I'll be using the 3% H202 as well.


Mice first, then if that works, I'll try an Apple 12" RGB Monitor case. I have a duodock that's quite yellow and worth a try too.

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Fantastic research and results! I typically avoid yellowed hardware I see on eBay (it often goes for less as well). Maybe now I can save some money de-yellowing it myself.

Until now, I thought the the only solutions were to mechanically remove the top layer of plastic (i.e. SoftScrub abrasive cleaner) or painting over it with paint that's a "close enough" match. Good to know there's a better solution.

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Fantastic research and results! I typically avoid yellowed hardware I see on eBay (it often goes for less as well). Maybe now I can save some money de-yellowing it myself.

Until now, I thought the the only solutions were to mechanically remove the top layer of plastic (i.e. SoftScrub abrasive cleaner) or painting over it with paint that's a "close enough" match. Good to know there's a better solution.


You really have to try it to see how effective it is. My mouse was my first test and it had yellow spots and unven yellowing. It was a mess. I went out at the end of the day to retreive it from the solution and could not believe the result. I tried my HD20 case then next day - it was really badly yellowed - also unevenly. Six hours later - and I have a uniform beige case - looks brand new.


What interests me is how the process does not leave you with a uniform "lightening" effect, with all the uneven markings still there - rather, it seems to remove JUST the yellow and leave behind the original beige surface. If you read the wiki it explains the chemical process that allows the selective removal of the yellowing.


Very rewarding.

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However, there are several examples out there of permanent damage as a result of this process (my belief is that this damage stemmed from unnecessarily high concentrations of H202). An example of a damaged logo

Lumpy, given that your badges have only been the older square shaped ones, and the example you provided was the newer type, I think it best to remove anything you can. These badges are easily removed by sticking a paperclip through the hole on the inside of the case and popping the logo off. My personal theory is that H202 of any concentration is corrosive to steel, which is what I think the later logos are made out of, and which causes a chemical reaction that dissolves the paint. FYI, I sampled a few of the old square logos and they are most definitely made out of aluminum which is neutral to H202. The inlaid apple-shaped logos I've sampled are too dark a metal to be aluminum. Most likely steel. Remove them, either way – better safe than sorry.


Also, Target stores offer 1 liter bottles of 3% H202 for US $.99. Walmart, K-Mart & Costco likely offer similar values.


One thought about dunking large items such as the rear case buckets of the compacts: the buckets themselves contain a large volume, which on the inside does not need to be de-yellowed. Take a plastic tuperware-type airtight container as close to the shape of the inside of the case bucket as possible. Fill it with water and place it inside the larger plastic container you're going to immerse your Mac in. Then add the Mac over it and fill the container with H202. It will take a much lower amount to cover the Mac since the water filled container beneath the Mac will displace a much larger volume of solution. This provides the advantages of the more evenly distributed low percentage solution and the low-cost of the gel.

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I will update the original post with the information on the potential corrosive effects to steel logo/stickers and I will also note the sources of cheaper H202!


With regard to large items and conserving H202 solution: Great minds think alike! I actually filled two Arizona Ice Tea containers (the large ones) with water and squeezed them a little before sealing them to make them a tiny bit narrower... Two of these containers fit into the rear bucket of a compact mac and decrease the volume of water needed to fill the tub to fully submerge the bucket!



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  • 4 years later...

Sorry to bump an old thread, but I don't like creating new ones if its not needed.


First, it appears lumpydog submerged the parts. While I have not done super extensive research on retr0bright, this seems like a better idea than coating repeatedly. I also know that with gel one can cover with plastic wrap. But I like the idea of dunking since it may provide the most even coverage and eliminates dry out 100%. Has anyone else done the dunk method versus the gel application?


Second. I feel I may have to try this in summer for best results on cases, but I would like to give a go this winter when for mice, keyboards, etc. It seems that UV lamps are hit or miss. Has anyone found a lamp that works perfectly for this application? I happen to own several UV high output lamps but lack starters and ballasts for them. Plus they are dangerous as they emit massive amounts of UVC. These are actually used for face tanners in tanning beds where clad glass and MUG6 glass is used as a filter. Maybe this summer I will create a box for one.

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I've done it similar to Lumpy with 20 Volume Developer I get from the beauty supply store in gallon jugs. I mix one gallon developer with maybe eight gallons of hot water and a couple of scoops of oxyclean powder (I mix it in the hot water jug and shake to dissolve) all in a clear, plastic tub. You really need some clear, sunny days to get it going well. It also seems to work better for me in the warmer weather. It can take as little as 2-3 hours to be "done" with some strong sunshine on it. Be sure to flip it every so often to get some even UV coverage.

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