When I went to my local metal works here in san diego, they have bins and bins of scrap metal, sheets, foil, scraps, corners, canes, etc. anything you could ever wish for. They also have a bin of scraps for artists, because as best that I can figure, someone there saw something interesting about that piece.
Usually, I cut, file and punch words and names into the thinner scraps of sheeting. However, while there, i saw these chunks and thought they had potential, but never did anything with them. There are two solid chunks and two stacks of sheet scraps, all listed separately to get in on the cheaper first class postage rates, I have separated them up into equal weights that will ship first class.