Don’t put cast iron in the microwave

No. Absolutely not.

Cast iron is metal. Microwaves work by bouncing waves around inside a metal box and those waves don’t play nice with other metal surfaces inside the chamber. Put a cast iron skillet in there and you’re basically inviting sparks, arcing, and a possible fire. The microwave can also reflect the energy back into the magnetron and fry itself.

Even if the pan is small or you think “it’s just for a second” — don’t. The metal will block the microwaves from reaching the food anyway, so nothing heats up except the pan’s handle and the microwave’s patience. Plus, cast iron gets incredibly hot in spots, which can crack the glass turntable or damage the interior.

There’s no safe way to do this. If you need to reheat something, use a microwave-safe ceramic bowl or glass dish. Your cast iron is for stovetop and oven only.

This is not where you test science fair projects.