Switzerland does something similar with what is left after trash has been burned. It is against the law for the left over ash (schlake) to contain more than 1%

Switzerland does something similar with what is left after trash has been burned. It is against the law for the left over ash (schlake) to contain more than 1% of metal. Therefore they extract it and sell it making a profit. https://www.srf.ch/play/tv/redirect/detail/d8f14e5f-c921-446a-89c8-8b73d5642260 https://www.srf.ch/play/tv/redirect/detail/d8f14e5f-c921-446... (Swiss German)