How to restore the color of dingy old Lego bricks

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UPDATE: Boing Boing reader Jody thinks these are two different flags, and I agree.

Here's a recipe for making a wonderfully caustic goop called Retr0bright that restores the color of of old computer cases and Lego bricks. It contains hydrogen peroxide, glycerine, vegetable gum, and sodium percarbonate.

Anyone who has dug their old computer or console out of the cupboard or loft for some retro gaming will probably have noticed that it maybe hasn't worn too well with the test of time. The plastics these machines were made of is called ABS and to make it flame retardant (just in case it catches fire after a marathon session) the plastics manufacturers added chemicals that caused the plastic turn yellow or, even worse, brown over a long period of time.

It was originally thought that the yellowing was permanent and that the only solution to this was to paint the plastic in its original colour and cover the problem up. However, a chance discovery was made in March 2008, by The CBM Museum at Wuppertal in Germany (, that immersing parts in a solution of Hydrogen Peroxide for a few days could partially reverse the process. This was initially taken up by the Amiga community in Germany ( and the idea eventually found its way to the English Amiga Board (, where a madcap collection of chemists, plastics engineers and retro hackers managed to perfect this concept and put it on steroids, with help from other forums.

Please don't brush your teeth with it.

The Retr0bright Project (Via Make: Online)