Reply To: Cleaning Pellets with ultra sonic cleaner?
An ultrasonic cleaner is not necessarily a non-trivial process. At the jewelry shop I worked in, the guys filing said they could feel the difference between metal that had been through the ultrasonic and that which had not (work hardening by the ultrasonic action.)
During my tenure, we found a chemical to replace hydroflouric acid (scary dangerous) for stripping investment. Only moderately dangerous, it would convert to hydrofluoric during part of the ultrasonic pulse cycle, then revert to the safer compound just after the pulse passed.
The upshot is that ultrasonic cleaners can really do stuff, not always obvious.
I’ve read that pewter, a lead-tin alloy work hardens, but anneals at room temperatures over a day or so. So it is possible ultrasonic cleaned pellets may show differences the first day, but not later on.