I've owned my microwave for 6 years. Clearly I'm not the most observant person in the world because I've spent my whole life panicking about accidentally putting metal in the microwave. Today I noticed a sticker on mine (inside the door-see picture) that clearly shows I should use a spoon when heating fluids. Couldn't believe it, so I got out the manual. Sure enough, it says I should always put a metal spoon into fluids whwn heating them, but not let it touch the sides of the microwave!!
How did I not know this. I've spent all my life believing if I put something metal in the microwave it will combust into flames!! Am I the only person in the world who didn't know this?