Rock tumbling is a fun and engaging activity, and a great hands on hobby for people of all ages. It can be relaxing and incredibly satisfying to take rough stones through all stages and end up with shiny, polished stones.
However, it can also be incredibly frustrating.
Sometimes you take your stones through weeks of tumbling, do that final rinse, dry them and....they are dull and look not at all as you hoped.
One potential cause of dull stones after tumble polishing is not getting them properly cleaned between stages. It seems simple enough, right? Just rinse them off and you are good to go.
Do a Rinse Run
If using a rotary, dump the stones and slurry out (into a colander or sieve), do a quick barrel rinse, then put the stones back in. Add water to the top of the rocks, and a tablespoon of Borax (or any powdered dish soap), and put back on the rollers for 30 minutes (or longer). This helps break up any thick leftover slurry, and helps get into any grooves or vugs that may be present on the stones.
If using a vibratory tumbling, you can do the same thing of dumping out, quick rinse, then refill adding more water and powder dish soap. You can also "cheat" by simply adding about 1/2 to 1 cup of water to a 5lb bowl and some soap (more to larger bowls) without first dumping the slurry. This kickstarts breaking up the thick slurry in any cracks or vugs.
Powdered dish soap won't lather up the way liquid dish soap. We often use liquid dish soap in our vibratory tumblers, but you do not need much. If you overdo it, you end up with a lathered slurry mess!
Utilize a Toothbrush or Scrubber
When cleaning the barrel, make sure to wash all parts including the rim and lid very thoroughly. Setting aside a toothbrush or similar scrubber for this will help make sure you get in all the grooves. The toothbrush is also great for getting in any cracks or holes in the rock to get all the slurry out.
Get a Spray Bottle or Dental Pick
When I rinse, I nearly always use a spray bottle to spray out grit and slurry from any cracks or crevices. I find this to be one of the most helpful ways to clean out tricky spots. It can get a little messy though since there might be some back spray.
Keep Separate Barrels or Bowls
It would be amazing if we could have separate barrels for each stage, but barrels are expensive. Instead, you could have a barrel the first three stages, and a separate barrel for the polish stage. This ensures that the silicon carbide grit from the early stages doesn't get caught in the barrel and ruin the polish step. This is an added expense, and not necessary, but can make it easier.
Know Your Media
Are you using ceramic media or plastic bead media with your stones? If you are using ceramic media, just make sure to wash it as well as you do your stones. If you are using plastic media, its best to not move the plastic pellets between stages. Keep any plastic pellets used in stage one for only that stage, and so on for the subsequent stages.
Remove Broken Stones
If you are in any stage beyond stage 1, remove any stones that have chipped during tumbling and set them aside. Chipped stones with sharp edges can scratch and damage other stones which will ruin the final product. Jagged edges also hold grit and slurry, and are more difficult to rinse out between stages.
Making sure everything is properly cleaned between stages really is one of the best ways to ensure you get a great finish on your stones. And remember, never dump rock tumbling slurry down the drain!