How to Whiten and Renew Yellowed Plastic

White is a color that goes well with everything and thus is a perfect choice for objects that don’t need to stand out. It’s also the most used color for walls and ceilings, ans so most light switches and ventilation covers are made of white plastic.

However, white ABS plastic has an Achille’s heel: it will turn yellow when exposed to the UV rays from the sun. In more detail, it’s the bromine that was used in the manufacturing process of old ABS plastics that will make its way to the surface and make the plastic look yellow.

That’s problematic for obvious reasons, and we can’t realy do anything to prevent it. However, we still can make things better by cleaning the yellowed plastic pieces and making them white again!

It’s a realluy simple process if you have the supplies needed and a little bit of time. So let’s get started!

40 Vol 12% Developer

Cling film

Latex gloves

Sunshine

As always, I did a quick video for those who don’t want to read the whole Instructable and prefer to see a video instead:

For starters, clean your plastic pieces from any dust.

Then, apply some cream onto the object and smear it around to have the whole surface covered.

Take some cling film and wrap the plastic piece into it. Make sure you cover all of the surfaces and that there are no holes from where the cream could evaporate.

NB: The 40 Vol 12% developer is a highly concentrated solution of hydrogen peroxyde so you really don’t want that on your skin! So make sure that you wear gloves!

If by accident you get some developer on your skin, stop what you’re doing immediately and run to the bathroom to rinse the skin with a lot of water in order to neutralise the acid as quickly as possible.

This is the step where the whitening takes place.

Place the plastic pieces under the sun and leave them there for at least a day. It’s the UV rays from the sun that in combination with the hydrogen peroxyde will make yellowed plastic white again.

I left my test subjects outside for two days but yours may need more or less time depending on the weather and the location.

Remove the cling film and wash the plastic pieces under water to get rid of the developer cream. Again, it’s a good idea to wear gloves while doing so.

With that, the cleaning process is finished! As you saw, there really isn’t that much work to give a refreshed look to those old yellowed plastics :)

I hope you enjoyed reading my Instructable. Stay creative, and have a beautiful day!