Hello, I just watched the new video from The retro future where he tried to fix a GBC. The repair is not really interesting (he just swapped the motherboard) but he used an ultrasonic cleaner to clean the GBC's shell and buttons. If you look at 1:38 you can see the A/B buttons look good, but at 10:24 some white came out of them. Have you noticed the same yourself or was it not visible before the clean? Also he said he won't clean the back shell because of the sticker, is it possible for the the ultrasonic cleaner to also remove or damage it?