Using a bolsa wood slab I can bring back the shine and thoroughly clean watch parts. The purpose of the balsa wood is to adsorb excess fluids and it is so soft you can punch diverts in for wheel pivots, then scrub away the tarnish using jewelry cleaner or lighter fluid. Then into the ultrasonic for final clean. No mess and reusable many times over. I have had great success with this method for vintage watches that have tarnished.