Don't be too afraid of shellac, it's easier than you might think. Modern transparent lacquers are durable but can go wrong in many ways, and are often impossible to redo without damage to the original japanning.
What ever you decide to use, the initial clean up process is the most important step to get a nice result. You need to choose a lacquer and polish that doesn't react to the finish already there; if it's not done right it can start flaking later on, turn whitish, blister like things can form,... Polyurethan lacquer is just as much job to get nice, if not more, and it smells stronger.
Shellac is disolved in achohol and often applied with a cloth (shaped like a round ball) or it can be sprayed on. It doesn't take two weeks to get layers of shellac on a machine, the indivual layer dry within a minute or two, very fast, and the next goes on one after the other. If you are fuzzy, you spend time polishing the last top layer with oil (if I remember correctly). Shellac have a slight tendency to shrink in the last hardening off process, to make it it even and flawless you smooth and polish it with a cotton rag. The smoothing step prevents any minor flaws appearing, the shellac finish will turn out shiny and transparent either way. One of it's main advantages is it's not prone to react badly to any previous treatmens of the machine. It's a very hard, durable finish.
Japanning in good condition can be cleaned with a damp microfiber cloth, well wringed up not to leave any dampness on the finish. For a clean up process you generally start with the gentlest methods, carefullness and patience is definitely required, and you amp it up from there. Some machines are easier to clean than others, and you don't really know until later. It just takes time what ever you do and there aren't much that speeds up the cleaning process. I don't like kerosene ether, it's very smelly and messy.
After cleaning, the whitish liquid type car polishes (with a very fine grit) will further lift up dirt and grime from the finish. Shellac seems to handle it well, but if the top layers are worn down to decals you need to work around them. You can sacrifise a vevety microfiber cloth or cotton rag for the application and inital swirling on, I don't use paper towels, but prefer and old washed out sheet or t-shirt, maybe cotton flanell, something extra soft for the buffing. I discard if after use.
Some lacquers might be more modern and stand up to dampness better, but they aren't easier to work with than shellac.
Last edited by Mickey2; 08-26-2019 at 08:48 AM.