Its the very first type of rock polishing I ever partook in, with my child hood christmas present.
After polishing hundreds of pounds, I give a lecture on the entire process. how to get the best polish, source stones, maintain and repair tumblers. I discuss rotary and vibratory. You can read the pamphlet that comes with your tumbler, but this course really exposes the science behind them, so that you can control the exact results every moment.
Tools required: none