Speaking to the calipers, since I'm in the rebuilding business....
Low value/common cores are not really worth much now. There used to be TONS of cores that we'd buy all day long for under $10 each...the real common run of the mill stuff. This was when the rebuilding facilities were here in the states, and a lot of these cores were sourced locally (or came back on core return pallets, but that's a different situation). Now, all of the big rebuilders are in Mexico. When we take that $8 core from Chicago, transport it from the shop to the parts store, the parts store the distribution center, the DC to the main supplier warehouse, and then from that warehouse across the boarder, the core has now cost money....since we've got $20 in transportation in it....then since it came from the rust belt, it might just go straight into the scrap bin. Cheaper to scrap it where it sits and just get a new unit from China....then we also have no labor cost to rebuild it, no 20-30% scrap rate to deal with (cores from the rust belt go to the scrap bin quite often), and it's just easier.