Can metal go in the microwave?
Do not heat forks
When you heat your leftover macaroni with a spoon, there won't be a flame in your microwave. A spoon is big and thick enough to absorb the heat. A fork, on the other hand, collects the electric current at the ends due to its long and pointed shape. This creates sparks and ultimately forms a fire hazard. Stick to spoons, only when really necessary.
Metal oven racks aren't a problem
What about metal oven racks and baking trays for combi microwaves? These objects contain a type of coating that's suited for heating up. This way, you can heat your food without sparks and your microwave doesn't catch fire.