This is what I used.
I used it with a hand drill. You have to go slow as if it's to fast or you spend too long in one spot you will melt / Warp the plastic. I would know because I did , and it took me a few weeks to find another original to replace it with.Also when doing it I suggest you apply some kind of polish as your buffing it off.
I had 2 months off from work because of covid during the winter months. The hardest is the lettering on the back side where the binding posts are. I had a few zws that needed restoring, so with trial and error I got better at each one. so here are some pictures of one that I bought from New York electric trains a couple months ago. this is a complete teardown, clean, service, repainted and tested. If anyone is ever looking to have theirs restored or purchase one from me when I have it available , let me know.