So sorry to be asking another question. I know I've read the answer somewhere but I can't find it.
I've got two very old 15k's and I am struggling to get them clean. The metal bits on one are black and the other they are dark brown. The metal polish I am using is not touching them (autosol). Should I be using some kind of solvent on them first? I am at the point of giving up on these two machines as they are in such bad condition but I really don't want to do that.