Used cooking oil (UCO), to give it its more formal name, has become one of the world’s most sought-after feedstocks for sustainable aviation fuel. Prices have soared as airlines scramble to cut carbon ...

“Gutter oil” is one of the most revolting substances in the culinary pantheon. It sprang from the ingenuity of Chinese entrepreneurs, who fished out used cooking oil from drains, sewers and trash cans ...