I tried acetone on an Amiga case, it just disolves it. give it a miss.
The "Cheddar Cheese" yellow colour is caused by photochemical ageing from UV light (keep those Amiga's locked in a nice, cool, dark cupboard). The only way to remove it is to take the top layer of plastic off. I have heard that Abrasive Diswasher liquids can do this without any visible damage but I have yet to try it myself.
