Also, just BTW...I sincerely doubt you're gonna get any takers on removing a huge pile of shingles by offering to let them keep the shingles. Brand new shingles really aren't *that* expensive, and I can't think of a single use for a huge quantity of used (or "old new") shingles. If we were talking about a pile of old steel equipment scrap or something, yeah...but not shingles.
Sorry..
Sorry..