No shellac on the chromed parts, at least originally. Chrome is hard, durably and doesn't tarnish, but in some cases it can start to flake off, and in extreme cases even wear off. Keep the machines in a dry heated room and the chrome will stay fine. You can polish it, and the metal under the chrome layer will shine up pretty well too. Early machine have nikle plating, and later have chromium. Nickle has an ever so slight yellow tint to it, while chrome are almost towards blue, at least in comparison.