When I bought my tumbler secondhand it already had media in it. I just bought some lyman media, tufnut part #7631396. I've tumbled some brass for a couple of hours and it's shiny but covered in the dusty residue from the media. Do I need to add some cleaning solution to the mix? I know a guy that uses "brasso", not sure if I should go that route and contaminate my brand new media. In the future I'm planning on moving to a stainless media in the future.