What stones can I tumble?
I haven't tumbled pieces with turquoise or pearls because I have read this can damage the nacre on the pearl and the turquoise being porous may absorb the liquid. I tumble the chains before I add these stones. I have tumbled amber without a problem but I only did this for about 20mins. Glass and Swarovski crystals have been fine. Hard stones like quartz and chalcedony seem fine but if I'm worried I tumble one bead first just to see what happens, make sure you put the bead on scrap wire so the little stainless steel balls don't get stuck inside.
I only tumble small amounts at a time, just because that suits my workflow. I usually check my pieces after 30-40 minutes and see if they need more time. The time will probably depend on what material and how much volume you are tumbling.
How do I store it?
When I have finished tumbling I rinse the barrel and stainless steel shot and then I cover the shot with filtered water with the water about an inch above the shot, all ready to use for next time. I tighten the lid and just leave it standing upright. I don't dry the shot and I have not had any problems working this way for over 2 years with the same stainless steel shot.