What would be the safest way to clean the tarnish of the dial indicators without removing the lettering? I used a dab of lemon juice and salt on a small portion of the dial and
it seemed to work but I didn't get any on the painted leters.

Phil

Once the silver plating is worn off, there's not much you can do about it.

The plating is still there, I don't know if tarn x would remove the painted numbers.

no real way to clean the dials. Kinda what you see is what you get.

They're not painted, they're produced chemically on the brass. I don't know what a silver cleaner would do to them. Maybe nothing. It might, however, leave the silver too shiny.