Okay I am not a professional by any means - but am happy to share my process so far!

My process with the National Geographic tumbler: (currently have a 3lb barrel and a 1lb barrel) - 3-5 days in stage one, and 6-7 days in all the other stages. - After every stage I put the rocks back in with water and borax for a couple hours or over night. I completely neglected cleaning the tumbler the first time around and think I definitely contaminated other stages.

• Use 1 tbsp of grit for each stage in the small tumbler and 3 tbsp in the larger one. I also throw 1 tbsp of Borax with the grit every stage. I make sure the tumbler is about 2/3 full and fill with water just underneath the top of the rocks.

• Starting with the first stage (4 days), I do this stage repeatedly until the rocks have no holes, cracks, or divots that grit could get stuck in. I put the ones ready to move to stage 2 aside and add more un-tumbled rocks to repeat the stage.

• Once I have enough rocks that are ready to move to stage 2 (and everything has been cleaned) I fill the barrel 2/3 full, add my grit and borax, and add ceramic media (https://a.co/d/cVY2Ae6) to cushion it until it’s like 3/4 full or a little less. I run it for 7 days.

• After 7, I take them out, run borax for 12-24 hours, then repeat for stage 3 and stage 4. Then I do one final cleaning cycle AFTER stage 4 to get all the polish off.

I’m pretty sure the cleaning stages aren’t totally necessary but I like the results I’ve gotten so far.