Who knew! Certainly not me, when I put a bowl of tomato soup in the microwave. It was a very nice bowl, with a gold-painted rim.
I thought it was a little strange when it started fizzing, but I had never microwaved tomato soup before so I didn't realise that it wasn't supposed to fizz.
However, when it exploded and left a gloopy mess over the walls and the door, I got a hint! Perhaps I should have covered the soup, but I was unsure of whether clingfilm-dipped soup would be poisonous.