wrote in news:868ea18e-fe16-44a0-9026-
:

You can lap the gears for improved running smoothness. But you should
use an appropriate non-embedding abrasive that breaks down after a
short period of use. Powdered turkey bone is one such material,
another is the old domestic cleaning powder named "BON AMI". I found
some at a flea market.

Timesaver lapping compound is a commercial product with the properties you
describe:

http://www.newmantools.com/lapping/time.htm

No affiliation. It was just the result of a search I did about a month ago
when I needed to deal with some tight gears for a project.