McCoy explained how he had trained Pleurotus mycelium to digest one of the most commonly littered items in the world: cigarette butts, over 750,000 tonnes of which are thrown away every year. Unused cigarette butts will break down, given time, but used cigarette butts are saturated with toxic residues that impede the process. McCoy had weaned Pleurotus onto a diet of used butts by gradually phasing out the alternatives.
