All depends on what a given scrapper has on hand.
I bought a good bit, mostly because on my very first trip I learned they were going out of business in a couple of weeks so I got what I could.
Much of it was fishing and dive belt weights (I live in a coastal county), but I also got various kinds of roofing lead. They had still more, but I was out of money and they closed up shop before I was able to buy more.
Only one piece has a lot of crud on it, a largish piece of some sort of roof flashing. Once I've figured out how to cut it into smaller pieces the adhesive and bits of tar will burn off when I melt it down.