Purchase a basket type permanent coffee filter and place in your
sink. Then, when draining your ultrasonic cleaner place the drain
tube in the coffee filter. Any stones or other small articles will
be caught in the filter and not go down the drain.
Items with loose stones can also be put in the filter and placed in
the ultrasonic cleaner. Then, if any stones fall out they will be
caught in the filter rather than dropping to the bottom of the
Brad Simon CMBJ