Guess I'm a lot like jsh, if it ain't broke..... I know I let my brass tumble longer than most but it has worked for me for years. If I put my brass in the tumbler today, it runs until the next day. I do know that a bullet seats quite a bit easier in the tumbled brass than a piece thats dirty so it must be cleaning the inside as well. Maybe not as good as SS media but it is cleaning it. I've been using a very fine media and it gets into the small cases and when time to empty, it pours out like water leaving a nice shiny piece of brass. IDK, its worked for me for a long time, hard to change. Maybe if my tumbler takes a dump I'll go stainless but until it does I'll just keep the old way.