Retrobright

A TRS-80 Color Computer 2 case showing significant yellowing

A TRS-80 after treatment, showing the yellowing largely reversed

Retrobright is a chemical mixture used to remove yellowing from ABS plastic computer and electronics cases, including computers that were manufactured by Commodore and Apple in the 1980s and 1990s, and various video game consoles and cartridges.

Yellowing is caused by both bromine and exposure to ultraviolet (UV) light. Many of the ABS plastics used in consumer electronics devices are typically “brominated”—combined with bromine as a fire retardant—to meet fire safety standards.

There is still some debate over the long-term effectiveness of this technique. Some have discovered the yellowing reappears, and there is discussion of factors that may result in this happening. There are also some concerns that the process weakens the plastic.

Composition

Retr0bright consists of hydrogen peroxide, a small amount of the "active oxygen" laundry booster TAED as a catalyst, and a UV lamp.

The optimum mixture and conditions for reversing yellowing of plastics:

• Hydrogen peroxide solution. 12% or 6% work the same.
• Approximately 1/4 teaspoonful (4.9 ml) per gallon (3.8 l) (1/3072) of Tetraacetylethylenediamine (TAED)-based laundry booster (concentrations of TAED vary).
• UV light, either from sunlight or a UV lamp.

Xanthan gum or arrowroot can be added to the mixture, creating an easier-to-apply gel.

External links

• Official website
• Un-Yellow Old Plastics - Retr0brite! (Make blog)
• Open source computer polish: Retr0Brite (Boing Boing)
• amibay.com - Retr0bright Support Thread