I normally use a little Dawn and a dash of Lemishine in my tumbler with SS pins to clean my brass. Tonight I was out of Dawn so I decided to try Simple Green. BIG mistake. My twice fired Lapua Brass came out looking more like tarnished copper than brass! Went and borrowed some Dawn from my neighbor and put it back in the tumble...no go. Have just spent several hours with Flitz to get it back to looking like brass. I suppose it was functional, but my OCD just would not let me use it looking like that! Simple Green will never get anywhere near my brass again.