Removing yellowing from Desktop PC plastic.

By marcson98 ·
I have an older model Desktop that the plastic has yellowed on over the years. Is there a way to clean it that will remove the surface yellowing and bring back something like the original beige color?

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There's just one little drawback here ...

by OldER Mycroft In reply to Removing yellowing from D ...

Invariably, whatever cleaner you might elect to try using on this old yellowed case, it would inevitably involve using nice warm sudsy WATER.

By and large, PCs and water do not mix.

Most old beige cases that have become a tarnished yellowish colour have usually spent the majority of their working life directly in front of a chain-smoker and most of the discolouration is down to nicotine stains. Usually, any attempt to remove this discolouration leaves the case looking like something kitted out for desert warfare with sand-coloured camouflage because some of the stains are just too ingrained into the casing as to be easily removable.

If you wish to try, I see no detriment in starting with a heavily dampened cloth loaded with standard domestic washing up liquid detergent. You just have to be careful none of the moisture seeps into and onto the innards.

I'd unplug it from all form of mains power before starting.

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things I have done

by .Martin. In reply to Removing yellowing from D ...

vinegar works on some cases
washing detergent works

as a last resort turpentine gets the stains out, but usually leave the case looking terrible

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Depends what has caused this

by OH Smeg Moderator In reply to Removing yellowing from D ...

As stated above Chain Smoking in or near the system is a common thing to cause this and it is part way cleanable though I have yet to find a good way of doing this. I just change the case with a new one if the computer is not one of the Propriety Cases.

The other big thing that causes this is the Plastic being exposed to direct Sunlight and as the Plastics are not UV Stabilized they discolor quite quickly. When this happens the only solution is to replace the case or if you want to go over the top just the adversely affected plastics.

I've seen people paint the entire case including the plastics in the past but if you do this make sure that you use a Non conductive Paint as it tends to get into places where you don't want it to get and can cause short circuits.


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Abrasives and Paint

by TheChas In reply to Removing yellowing from D ...

The yellowing of beige plastic pieces is part of the natural aging process for most plastics.

To restore near the original color, you need to use an abrasive cleaner / polish on the plastic parts. A good powered general purpose detergent or motorcycle helmet polish can do the job.

The problem is that you abrade away a layer of the plastic and the next layer down is software and will both scratch and discolor much quicker.

My recommendation would be a good cleaning followed by using spray paint for plastic models.

Yes, you will need to remove the panels from the case to avoid damage to the computer and drives. Plus, you will need to remove the actual switches and LED indicators.

On the plus side, you can choose any color you like.

If you have access to an airbrush, you can custom mix colors to your taste or decor. Just remember to only used paint designed for plastic models.


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2 ways.

by seanferd In reply to Removing yellowing from D ...

If the yellowing is caused by collected substances such as cigarette smoke, the best option is a *dampened*, not at all wet, cloth with a degreaser agent. Wipe repeatedly with the degreaser, alternating with a clean, damp with water only cloth. Rinse it out frequently. Continue until nothing else comes off.

Degreaser, like Mean Green, Greased Lightning, Simple Green, etc.

If it is natural aging of non-painted plastic, something abrasive will help. Don't use 60 grit sandpaper, but something very fine. It will take a lot of work, and you can't let any dust get into the system. ***I do not recommend this at all.***

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Mohawk Safety Solvent

by OH Smeg Moderator In reply to 2 ways.

Is also quite useful for cleaning Plastic Parts. It's chemistry doesn't damage plastics and it has a very high Flash Point so it's not likely to burst into flames unlike some other solvents can.

Down side is unless you do a lot of this type of work Mohawk is out of the question as they only supply in 20 Liter Drums as the smallest size available. I buy it in much larger amounts and love it. It's great for cleaning contaminated M'Boards.


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by seanferd In reply to Mohawk Safety Solvent

So, it is flammable, though?

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Well I wouldn't guarantee that if you waved a Lit Gas Axe

by OH Smeg Moderator In reply to Sweet.

Over the fluid or through the fumes that it wouldn't go up. But if you use it near electric Motors that spark when they run it isn't enough to set it off.

I can smoke over it and work at the same time. I started using that stuff over 30 years ago when I was fixing Sewing Machines as it didn't adversely affect any Plastics in the machines. The more that things change the more that they stay the same.


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by seanferd In reply to Well I wouldn't guarantee ...

All I really wanted to know was, if I were determined, I could set it on fire. :^0

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Case mod

by santeewelding In reply to Removing yellowing from D ...

After the motorcycle helmet polish, take everything apart and stuff it into the helmet.

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