Gun show "Bag-O-Brass" is usually always a disaster waiting to happen. A lot of this stuff is range pickup brass that's been shot out and left. Guys will pick it up, take it home and clean and sort it, then it's off to the next gun show to make a quick buck. These guys normally don't take the time to properly sort this stuff, and look for things that give evidence the brass is shot out. The guy buying it is often lied to and told it's, "once fired range brass". You can run into good deals from time to time. Once I found a guy who had 2, 5 gallon buckets of .38 Special brass for $10.00 a bucket. I bought both. I asked why so cheap and he said most were military with crimped pockets. The stuff took me forever to prep, but when I was finished I had close to 5,000+ rounds. All of it was good.
About half was Nickel and the other half brass which I sorted because Nickel cases can scratch resizing dies, even Carbide, and it will leave small scratches down the length of the case. So I resized the Nickel cases with an older Lyman Carbide die I had learned that lesson on. I'm always skeptical when I see lots of brass for under 50% of what it normally sells for. There is usually a reason for it. You can't polish away wear and tear. Bill T.