After gassing for a Virus since I started making music 22 years ago (time flies!), I finally caved in and bought a used Virus Snow 
But as you can see, despite its mint working condition it was quite dirty and yellowed by the time (vendor’s pic, as I forgot to take one before working on it):
So after a full proper cleanup with alcohol, I wanted to go a bit further and see if I could restore its original color a bit, especially for the buttons that looked very yellow-ish (worse than it looks in the pic). After looking at some retrobrighting techniques, I decided to try and went with a full teardown.
First I removed the bottom PCB (forgot to take a picture of it), which contains the screen and the RAM battery under it.
Then I removed the second PCB with the buttons, quite yellow at this point.
I bought 40% salon cream and first went with the heat cooking technique, putting all buttons and knobs in a pan with water and some salon cream, and left it for about 3h at 60ºc while stirring from time to time. It was a bit better after than, but the buttons still were too much yellowish for my taste so I went with different technique, putting salon cream directly on it, then put them on an aluminium covered plate, and cover everything with transparent plastic. I left the plate for 3h under the sun, and it definitely removed the yellow part!
Here are the parts before putting everything back together.
You can definitely see the improvement on the buttons’ color:
And here’s the final result:
I’m pretty happy with it, though you can see that the top metal case paint also suffers from slight yellowing, and the freshened buttons’ color makes it a bit more obvious. As retrobrighting only works for plastic AFAIK, any idea for a restoration technique I could use to restore the metal front panel color?