I have a few US Aristocrats, which I was unable to clean completlely due to fear of damaging the gold plating and also a type M adjustable Schick injector. I have a small ultrasonic cleaner, but I think if I let the gold plated razors stay there longer it might damage the plating and the same goes for the plastic/bakelite. I also tried scrubbing them with a brush, but since the razors can't be disassembled, some areas are hard to reach and very hard to clean. I've also broke the handle of my G1 Schick injector when placing it in methanol and then in hot water.