By jewelry cleaner he just means a cheapo $30 ultrasonic cleaner (which are advertised as jewelry cleaners). The normal cheap ones will only allow a 3-5 minute burst of operation.
I sit mine by my paint desk and if I keep hitting the button for about an hour (at which point the machine almost melts itself...in fact I melted the plastic basket!) they can be stripped completely - take them out and brush them with a toothbrush while rinsing them.
Often times though I'll toss them in the cleaner and not hit the switch till the next day or so. Good stripping solutions can clean the model without any ultrasonic use ---- it just vastly speeds up the process.
Plastics don't clean quite as easily, occasionally they lose a bit of their crispness around the edges and the plastic is often stained a colour from the paint, but that's all fine - they prime perfectly well.