What happens if you put metal in microwave?
Metal in a microwave oven can be hazardous to yourself, your food, and your microwave oven. Metal inside the oven creates short circuits that reflect the microwave energy rather than absorb it. This can cause hotspots, arcing, and can ultimately destroy the magnetron tube
Metal in a microwave reflects the microwaves. You can put metal in the microwave if it has a smooth, curved shape. If the metal is rounded, it won't arc. A metal bowl, for example, is fine! But don't put in metal like crinkled aluminum foil or has multiple sharp corners like a fork.