I've never looked into this before. Can you tumble with the pins and not the liquid solution on a vibratory tumbler?
I suppose you could. I don't think the pins will do much without the liquid. Also, the stainless pins are not really cheap. 5lbs does not cover all the brass so when they tumble in the rotary type tumbler they will still do their job as they are flying around in there. If you have a vibratory type you would have to have the tumbler filled up pretty high with pins or they would not contact the cases. That would not be cheap.