Microwaving an empty metal can, such as a soda can, is extremely dangerous and should never be done. Microwaving metal objects can cause sparks, fires, explosions, and serious damage to the microwave oven.
When microwaves encounter metal, they can't pass through it, and instead, they get reflected back to the microwave's magnetron (the component that generates the microwaves). This creates an intense build-up of electrical energy, which can cause electrical arcing and sparks. If a metal can is placed inside the microwave, the microwaves will interact with the metal, leading to potentially catastrophic consequences:
Fire Hazard: The sparks and electrical arcing inside the microwave can ignite any flammable material inside the oven or on the metal can itself. This can lead to a fire that can spread quickly.
Explosion Risk: The pressure inside the sealed metal can will increase as the microwaves heat the air and liquid trapped inside. Eventually, the can may explode, sending hot metal shrapnel flying in all directions, causing severe injuries and damaging the microwave.
Damage to the Microwave: The intense reflections of microwaves can damage the microwave's interior, including the magnetron, waveguide, and other components, rendering it unsafe or inoperable.
To ensure your safety and prevent any accidents, never put any metal objects, including empty metal cans, inside a microwave oven. If you accidentally put metal in the microwave, stop the microwave immediately, unplug it (if safe to do so), and consult the manufacturer's instructions on how to proceed. It's crucial to use microwave-safe containers and follow the recommended guidelines for safe microwave use to avoid any potential hazards.