When I excitedly bought my Lortone tumbler to make all my sterling silver and copper shiny and pretty, I carefully read all the information I could find about how to correctly tumble polish my pieces.
I learned that I should add the shot, then my pieces, and that the water level should be about 2/3 full - just under 3/4; depending on how many pieces were in the bucket. I learned that I needed a burnishing compound of some sort - the first time I bought some with my tumbler to be on the safe side, although I had heard that "Dawn" dishwashing liquid would work equally well.
I set out to find some "Dawn" but it isn't available in my area of Canada - perhaps not at all in Canada. I wondered how Dawn could be that much different from any other dish soap for the purpose I needed it, and despite all the advice I'd read that Dawn was the only choice, I used what was beside my sink one day, which is "Sunlight". Guess what? Works perfectly! I would have no hesitation to go ahead and use a couple squirts of whatever you have on hand.