[jamesqf]

Apropos of this, an interesting idea from today's news:

If the holy grail of medieval alchemists was turning lead into gold, how much more magical would it be to draw gold from, well, poop? It turns out that a ton of sludge, the goo left behind when treating sewage, could contain several hundred dollars’ worth of metals—potentially enough to generate millions of dollars worth of gold, silver, and other minerals each year for a city of a million people.

Sewage sludge could contain millions of dollars worth of gold | Science/AAAS | News