Let me start by saying I have not used a tumbler with dry media in several years. I wet tumble all my brass.
Today I wanted to tumble some rounds that I put together that had an excess amount of lube on them. My tumbler was set up with old powdery lizard shell media. IIRC. The rounds immediately had the powdery stuff stuck all over. I needed to dump all that media and tumble again using clean corn cob media.
They finally got cleaned up.
Joe