If Bezos, Musk, Gates, Zuckerberg (any you guys lurking) would give me $50 Million or whatever to help clean up the world, I would buy a portable smelter and haul it around the country to swap meets and buy up all the rusted out car parts, cheap junky used tools, holed junk radiators, Ugly as snot 1970's brass Knick knacks, on and on that litter the swap meets, etc.
Melt it, send it off to the mills to make something useful.
The carbon footprint of not hauling the same worthless stuff for years to the swap meets would be incredible.
I actually felt a little guilty pleasure one year in the Dallas area when the swap meet was hit by an unexpected wind blast, over 65 MPH according to the news, the flipped over, among other things, a group of tables that had the UGLIEST pottery and glass doo dads ever seen and there were very few survivors.