a sonic cleaner works by cavitation, which is, as i (don’t)
understand it, an action by which sound waves travel thru the
liquid and strike an object (the walls of the unit or the object
being clean) and bounce away leaving a cavity that is filled by
the next sound wave, causing litlle impacts of water with
detergent (or whatever solvent) upon the object being cleaned.
if one leaves most metals in the sonic for excessive amounts of
time, it will cause ‘white’ (unpolished) spots, especially on
flat objects.if there is excessive dirt in the solution, this
can cause these spots prematurely. some aggressive cleaning
solutions will cause spots on silver fairly quickly. if two
items are touching each other, they will vibrate against each
other and cause these irksome spots.