Related: As a 9-10 y/o kid in the 70s, I lived close to a factory in Tucson that made those crude, cheap latex Halloween masks. They would discard the ones that didn't turn out right (paint was wrong, the seam in the wrong place, torn, etc.) on a pile out back of the factory. Of course, the neighborhood kids would come and choose masks out of the pile to play with, and we'd come back every week or two to see what was new.
The first time I saw that 10ft tall heap of failed, discarded monster faces, some of the older ones melting into each other like something out of The Thing, it creeped me right out, though I didn't really understand why until later.