Keyboard Restoration
2026-02-21
Retrobrighting the Keycaps
The keycaps had the typical vintage yellowing and dark discoloration that affects ABS plastic over time. Bromine, used as a flame retardant in ABS, reacts with UV light over the years and causes the plastic to turn yellow-brown.
The Hydrogen Peroxide Method
The fix is hydrogen peroxide. I used SalonCare 40 Volume Creme Developer, a hair salon product available at Sally Beauty Supply. It contains approximately 12% hydrogen peroxide in a thick cream consistency that clings to plastic parts — essentially retrobright in a bottle.
What You Need
- SalonCare 40 Volume Creme Developer (16 oz bottle)
- A pot large enough to submerge the keycaps
- A thermometer
- Kitchen gloves — the cream irritates skin
- Warm soapy water for cleanup
Process
I used the heat method, which replaces UV light as the catalyst for the hydrogen peroxide reaction. Heat provides more even coverage since all surfaces are fully submerged, and you don’t need to wait for a sunny day.
- Remove all keycaps from the keyboard.
- Fill a pot with SalonCare 40 Volume Creme Developer and enough water to fully submerge the keycaps.
- Heat on the stove at low heat — use a thermometer and keep the temperature low. You want a gentle simmer, not a boil.
- Submerge the keycaps and let them cook. Check periodically — results are typically visible within 1-2 hours depending on the severity of yellowing.
- Remove and wash thoroughly in warm soapy water and allow to air dry before reinstalling.
TODO: Add before/after photos.
Keyboard Cable
The keyboard cable on the Compaq Portable 486c is a very proprietary connector and the cable becomes brittle and falls apart with age. Mine was damaged but still functional enough to tape up and keep using. A future project is to custom coil a replacement cable.
TODO: Add photo of the cable and connector.
Credits
The retrobright technique was popularized by The 8-Bit Guy (David Murray). His experiments showed that heat can replace UV light as the catalyst for the hydrogen peroxide reaction, making the process more consistent and accessible.