deskthority

Maybe you have seen how retrobrighting went wrong with the Osborne 1 on The 8 Bit Guy:
Well, this is how it how it goes most of the time when using the hydrogen-peroxide cream technique. However, I used the technique of submerging the plastic keycaps into 3% hydrogen peroxide but for experimentation purposes I only used enough to cover the keycaps half way and this is the strange result: The Keycaps are gray from factory as you can see from the keycap on the right. However, the keycap on the left was left halfway submerged in the hydrogen peroxide and where there was no hydrogen peroxide, it became white. This was after less than 3 hours under the sun.

However this is how it looks after 4 hours under the sun and completely submerged under hydrogen peroxide:
Left: how it looked before retrobrighting it, right: after completetly submerging it under 3% hidrogren peroxide for 4 hours under the sun.

It didn't went white being more time under the sun and with more hydrogen peroxide (Its factory gray color remained intact).

Tips:

• Avoid having air bubbles that can lift whatever you are retrobrighting.

• Check after 3 hours if it's ready because it can overbright the plastic.

In the pic of the 1 byte guy's caps you can clearly see where it looks like someone unevenly coated the caps. The damage creams do is highly visible, so troubleshooting the issue and avoiding it should be very easy. I'll never understand why anyone would ever use that option.

Your caps look really nice

I used the cream method for my Omnikey Case for the lack of a box that was big enough and translucent.

The key is to apply new, thinner layers of cream on top of the ones before in regular intervals to avoid the marbled look that appears when you unevenly coat your stuff. I did this every half hour in the beginning. Eventually, I wiped off all layers and repeated the whole process but in 1h intervals. It turned out pretty much perfect.

I'd always recommend using liquid peroxide tho, whenever possible.

Sorry but I don't understand why would you apply the retrobright technique if the plastic will return to its old "yellowish" color? I did several retrobrights and after some time, the old color returns.

Well, that's easy to understand for me regarding the two Apple M0110A cases, that I use every day: Before retrobrighting they looked dirty and disgusting, afterwards they look clean and beautiful.
After nearly 2 years I can see not the slightest hint, that the yellowing might come back. Should this happen after 10 years, I will simply repeat the process or - more likely - I will be using different keyboards/cases by then.