I have used corn cob media since I was taught to reload way back when I was 10. We tried different snake oil media's with special additives with little improvement.
Found its better to have several tumblers and as big as you can afford,do not over pack the brass and let it go for as long as you can. Braso,nu finish,pretty much any of those help.
As I became more of a uspsa 3 gun shooter I stopped caring so much about shine. Although for my long range tools I'll still put the work in to make sure each round is as perfect as I can possibly make it.
Found its better to have several tumblers and as big as you can afford,do not over pack the brass and let it go for as long as you can. Braso,nu finish,pretty much any of those help.
As I became more of a uspsa 3 gun shooter I stopped caring so much about shine. Although for my long range tools I'll still put the work in to make sure each round is as perfect as I can possibly make it.