Hannah - The first thing that I would suggest is that you use a
deburring compound with your abrasive media. 910 is for use with
polishing media such as steel or porcelain. While polishing, you want
an acidic solution. For abrasive media, the liquid solution should be
on the basic (alkaline) side. When you mix up what you should use, it
doesn't work as well as it should.
Since 910 is somewhat acidic, the warnings make sense. Your body is
mostly water. If you mix 910 with water, you get an acidic solution
and if the water is part of you, the result is not good.
While you can use dish soap for the steel, it won't work as well as
the prepared solutions. Washing dishes with hand soap is not as
effective as using automatic dishwasher solution. You really don't
want to put your hands in the stuff for a machine. I've tried the
automatic dishwasher stuff in my tumbler. It simply doesn't work as
well as the specially prepared burnishing solutions. Soap is intended
to emulsify fats. You don't have a lot of fats on your jewelry.
Bottom line - use the stuff intended for your media. If you are
using green triangles, use a deburring compound, not a burnishing
compound. I choose to use concentrated liquids for exactly the reason
that you are concerned about handling the powdered 910.
For more get the book I wrote on tumbling - Tumble
Finishing for Handmade Jewelry. It's available from most of the