I didn't take a before, or at least can not find one if I did, but I retrobrighted this set
Show Image
(http://i426.photobucket.com/albums/pp349/lysol8086/16314ccd.jpg)
The casebody shows how badly it was yellowed when I received it, which I still have not gotten around to. You can see the difference in color where the Amiga badge is missing in then upper right. Also the first pad printed caps (red A 1.25, sideprinted numpad, and the windowed caps) I have done so with, which came out unharmed.
Looka great! I have a semi-precious G80-2100 that will need both keycaps and case retrobrighted. I plan on submerging in 30%H2O2 I have access to and was worried about bleaching the black firstshot.