Peroxide to whiten yellowed keys

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Using a brush I applied gel which contains hydrogen peroxide (this stuff is normally used to bleach hair a.o.) on the ‘white’ keys of an old midi controller / keyboard the keys of which had turned yellow with age. Each part I’ve packed in a closed plastic bag, so that the peroxide does not evaporate too fast. Unfortunately we’ve had lots of clouds and little sun during the daytime, so this may take a while.

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I’ve done this with some other plastic things with success, so I’m hopeful this will work as well.

Has anyone done this / any experiences with this?

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I’ve got no experience of this but I do have a 76 note controller that needs whitening. Let me know how you get on.

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There is this video where Adam Savage used hydrogen peroxide to whiten restore the lid of a Nagra tape machine. I remember that he was only partially successful.

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I’ve seen that video and was puzzled by what he was doing. Peroxide is used to whiten yellowed plastic. The lid of his Nagra was never white (in fact it was transparent), nor has it yellowed. So I was not expecting anything to happen and in my opinion the video shows that indeed nothing much happened. The small differences visible between the start and the end I would attribute to him cleaning the lid. So I think he used a method that was not fit for what he was aiming at. I’ve seen several people whiten old transistor radio cases successfully that had gone yellow and I have successfully whitened a weather sensor in the past few days. So I know the method works / can work on plastic, I’m just not sure whether it works on all plastic, what amount of peroxide to use and what time it should stay in the sun and ‘how much’ sun is needed anyway. Would it work on an overcast day as well?

I’ve taken pictures of the keys beforehand and will do so tomorrow and report back.

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It’s not only a question of the different kinds of plastic (the bakelite of the early radios, PVC, etc) but also a question of what caused the yellow tint in the first place. Exposure to sunlight, heat, dampness, mould, skin oil, oxygen, pollution… can have different effects on different kinds of plastic.

As for the sun, I was able to get a couple of badly yellowed monoblock plastic chairs, that were left for years in a damp basement, completely whitened just by leaving them out in the sun for a couple of days. No peroxide, just the sun. Of course, your mileage will vary!

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While “best” might be a bit of a click-baity overstatement, I have seen an awful lot of evidence that it works pretty well.

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The retro games group I help at has used this technique successfully in the past to restore yellowed commodore 64 cases. I don’t see why it shouldn’t work on synth keys if they’re made of the same plastic.

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I know, but there is a difference between seeing things done and doing them yourself.

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The plastics that go brown have brominated fire retardant in them that breaks down, I’ve heard of peroxide being used to restore those. I am not sure if white plastic (styrene, ABS etc) that goes yellow is undergoing the same degradation process.

The strongest over-the-counter peroxide I have found in the UK is about 6% concentration, and peroxide breaks down into water and oxygen when stored.

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I don’t know any details of what is happening chemically speaking when plastic turns yellow, but I’ve found that the peroxide trick works. The strongest concentration we can get over here in the Netherlands is 13%. That is what I used. It degrades in the sun, so it comes in non transparent bottles. The stuff I use is used as a hair product. I will post a picture later this week that will show the keys before and after the process

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something like that :grin:

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Granted, there can be some side effects using these hair products, but it does whiten the keys !

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The results are in, but they are not overwhelming in this case.
I’ve tried to replicate the lighting situation as close as possible when making the pictures shown below.

These are the keys before applying peroxide:

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These are the keys after the procedure:

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I can see some but not much differences, but I must say:

1: I’m not a photographer, so the light or my phone’s camera may be playing tricks on me here.

2: there was not a lot of sunlight the last few days

3: I do not know anything about the quality of the peroxide-gel I was using. Maybe the gel is not suited for this use case.

4: I used an ordinary transparent plastic bag to put the keys in. I have no idea about whether enough UV-light passes through this plastic bag.

5: I have no idea how the result of the procedure can be expected to vary with the type of plastic involved.

6: I have no idea how much peroxide has to be applied, how often and how long it needs to be exposed to how much UV-light.

Yep, there are a lot of variables involved and no doubt I forgot a few here.

From remembering the keys when I first saw them to when I see them now, I still have the idea that they are distinctly more white than they were. When I look at the non treated side of the keys and compare that to the treated side, there is a more distinct difference in color.

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This is for people who are new to keyboards (the rest of you can skip this): to the left you see the bottom side of some of the keys, to the right you can see the top side of some keys :wink:

The bottom side of the keys on the LHS show the kind of ‘yellow’ I remember from seeing them the 1st time.

In conclusion for this experiment I would say that the results are only vaguely positive. But given there are a lot of variables and a lot of unknowns, I would not dismiss the procedure.

Furthermore, to contrast this result below you see a picture of a sensor of a weather station I treated in the same way. Here the colour change between the plastic before treatment (right hand side) and after the treatment (left hand side) is more apparent (althought the light in the picture is different). I treated the plastic 3 times with the peroxide-gel and it was exposed to sunlight (well it was mostly overcast) for 3 days.

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I used the same gel, the same plastic bag to enclose the sensor in while it was exposed to sunlight. But this may be a completely different material to start with, so …

All in all, you mileage may vary when trying this.

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Not just your camera! All sort of things can happen.

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