I have an old B&S #19 0-1" micrometer that is hard to read. The numbers have been partially obscured because the metal has darkened with age (and abuse by a former owner).
I lightly sanded the dark areas but it wasn't enough to bring out the engraved numbers. I then used a magic marker to fill in the engravings. That helped for awhile but it turns out that the "permanent" designation on the magic marker isn't quite accurate.The black color quickly disappeared.
So I'm looking for suggestions on what coloring agent to use instead.
Gary