I deyellowed my Mac Portable's spacebar using this:
• 3% H2O2 (normal drug store kind)
• 1 teaspoon Oxiclean (boosts the H2O2 slightly)
• Small transparent plastic container.
• SaranWrap (as a cover to prevent evaporation)
• Aluminum Foil (place shiny side up, under the container)
• Two angled metal pieces to hold spacebar in place
• Masking Tape to hold down the metal pieces
The metal pieces are hooks for hanging things on the wall, which I happened to have in my toolbox. The spacebar has 2 pieces of plastic under it, which have slits that fit onto the metal support bar on the keyboard. I fit the spacebar slits onto the protruding part of 2 metal hooks and then taped the hooks to the bottom of my Tupperware container. The metal of my hooks was thin enough to make that possible. The taped-down hooks held the spacebar in a fixed location in the center of the RetroBright liquid. Without them, H2O2 bubbles would make the spacebar rise and flip. When you deyellow a full keyboard set of keycaps, you have no choice but to let them float, but when doing only a spacebar, you can do right.
I left it outside in direct sun (almost no clouds) from about 9:00am to 5:00pm and then washed it off with warm water and let it dry. Outside temperature ranged from 20 to 25 degrees Celsius (68 to 77 Fahrenheit).
It deyellowed ever so slightly brighter than the rest of the keys, but since it’s a different plastic than the other keycaps, that’s probably the biggest reason. It did not turn white. I looks Apple Platinum to my eyes. And what you see in my photo are the fully cleaned Keys. I removed and then soaked all the keycaps in 55°C hot water with lots of hand dishwashing cleaner squirted inside. The soak was for 30 minutes, and then I took a toothbrush and scrubbed every single key perfectly by hand, ensuring no dirt particles at all. I did not deyellow them.
The Polycarbonate plastics on the Macintosh Portable don’t really yellow over the years, most likely due to the absence of flame retardants. I wish all Macs were made this way! Only the spacebar yellows over time, due to being some other kind of plastic.
Hope this encourages you Portable owners with yellowed spacebars to remedy the situation!
