Ceramics To raise awareness about how we handle our food, I made this poisonous fruit bowl. Out of hand-scooped clay, from the polluted river nearby. With silt and poisonous engobes, which still give off. If you put a fruit in it, blue/green stains would appear. Fortunately, when you rinse off the oxides, you also rinse off the anti-insect poison from your sprayed food.