I agree with the others, as well. I have collected Supraphonics, and have never messed with the interior. It won't rust or tarnish. And if there is a date stamp on the inside, you don't want to accidentally wipe it off.
As far as the exterior goes, I like to use eyeglass cleaner and eyeglass microfiber cloths to remove fingerprints, sweat, etc., and brighten the chrome. Other cloths and cleaners can leave small light scratches on the chrome plate.
Acne? Well, acne happens despite one's best efforts. Some Supraphonics have very few "bubbles," while most have at least moderate acne. Some people have said that heat and humidity play a role in the amount of acne, but I'm not convinced that's true. I think the differences in the amount of acne has more to do with which subcontractor prepared the shells for the chrome plating.
As we have learned, chromium and aluminum hate each other, and aluminum will corrode if it comes in contact with the chrome. The aluminum shell is coated with layers of nickel and copper before the chrome plate is applied. Any imperfections or "thin-ness" in these protective layers will allow the aluminum and chrome to attack each other, resulting in the aluminum corroding and "pushing" the chrome plate off. Ouch.
Regards, mb