Over the years, I have collected a number of screws, bolts, nuts, etc. that at one time belonged to things, but no longer do. they are perfectly usable, and I have saved them, assuming that I would find uses for them eventually, but mostly they just accumulate. Is there an organization of some kind that takes donations of such things?
How 'bout my grandpa (stubborn bastard doesn’t throw ANYTHING away.)
The cost of each screw is less than the cost of paying somebody to sort a bunch of random screws, so any organization that needs screws will just buy them rather than pay someone minimum-wage to sort them.
At best, you might be able to sell them by the pound to a local scrap-metal dealer.