Back to looking at the potential of the waste. Some of the leather is rejected because of it's flaws - marks and holes which actually show the history of the animal from which the skin came. When I filmed myself marking and cutting a side of leather for L&D, it had a brand mark which I cut around with the letters "OA"
It is interesting that although leather is a natural product and hence will bear the natural imperfections which are evidential of the acts of the animal which formed the skin, customers of leather products expect the leather to be perfect with no marks. Hence leather is often refinished with a plastic life coating after the marks are abraded.
I think that these marks show a connection between the material and the source - which is something that can have real value. These parts are rejected, but maybe they are the best parts?