For us, old nails and lumber used on previous projects got straightened and reused. Years ago I helped tear down an old building, and started straightening nails as we went. The one who bought the building said just throw them away. Oh the trama, so so contrary to what I grew up with. My depression era parents, vs physician's sons turned dairy farmers. We would have recycled everything, nails, lumber, iron, piping. They did not. They wanted the 2x10 rafters and that was it, scrap the rest. Memorable experience.