Proper cleaning before tumbling

I clean a lot of my tumbling material by simply throwing them in a large tumbler or cement mixer along with all the chips from breaking up the rocks. The chips act like a grit grinding off caliche, lichens, etc. and there will some grinding of the stones.

I have even got polished stones from tumbling in just water alone, but I find the rhyolites do best for this process. With no grit, the stones also keep more of their natural shape rather than rounding.

Anyone else have any methods? I have used various small brushes, toothbrushes, denture brushes, and various natural cleaners. However, some of these cracks are so thin! Has anyone tried hydrogen peroxide, or even bleach?

The idea of the coke set me thinking, I am using an ultrasonic cleaner to clean out polish on my cabs, and as some folks said they were hesitant as they worried about the ultrasonic cleaner breaking up their rocks, as a test I am doing it on everything! And so far, I have not had a breakage. So the ultrasonic, fingers crossed, so far is safe enough to use from what I can see.

Perhaps using coke or vinegar or lemon juice in an ultrasonic would help in this sort of situation?

Agree strongly! Horses for courses

I mostly collect agates, jaspers, and pet wood in western CO and Utah. When I bring something home that is too pitted, cracked, etc., I'll see if it might be a good candidate for slabbing and polishing with my vibratory flat lap. If they don't look good for that they get tossed into the rings around the fire pit in my backyard. My fire pit is surrounded with agates, jaspers, and partially tumbled stones that I decided wouldn't be worthwhile to finish tumbling. I'd like to start making cabs with some of that material one day.

Thanks- absolutely makes sense - I have tried to collect mostly stones that will tumble well, but sometimes the colors are so striking, I just have to grab them!