The world is a step closer to recyclable electronics, with the discovery that processed mushroom skin could be a biodegradable substrate for computer chips. A PhD student working with Martin Kaltenbrunner of Johannes Kepler University in Austria, studying wood–mushroom composite materials for insulation materials, found that Ganoderma lucidum mushrooms form a compact protective skin around the wood shavings on which they grow. He was able to peel off large sheets, which resembled thin sheets of paper, and the strong, flexible, current-resistant and heat-resistant material is perfect for a circuit substrate. It could be bent more than 2,000 times and folded over multiple times without losing its electrical resistance, and metal circuits could be constructed on the skin. The fungal skin hits the “sweet spot” for degradability, lasting for a long time when kept dry but degrading in a standard household compost in two weeks or less. The world generates over 140,000 tons of electronic waste each day, and electronic circuits made of multiple computer chips on plastic circuit boards are a major hurdle to recycling.