These really do work well but on trigger sears I never use them as I like to try and keep the shape as close to original as possible and wet dry followed by autosol on a flat surface is more precise.
Those in 60+ age group will remember ink rubbers. Used to wreck your paper but great for shining up steel similar to what you describe.
might be useful for air rifle cylinders,my old gunsmith used polishing stones for trigger sears on S&W and Colts