Hello It would be awesome if anyone can help me with this. The center of the top wall of my microwave oven seems to have melted and the coating has formed boils about 1cm in radius. My roommate thinks its because of the evaporation of oil in the food that someone microwaved for too long, sticking to the top and melting the plastic coating. He says the boiling point of oil is about the same as the melting point of the plastic, and therefore that was what happened. This doesnt seem plausible. I think its because of someone microwaving something pressurized (there are four of us using the oven and no one is confessing to misuse.) What do you think happened? Background: We mostly use the oven to microwave vegetables or frozen food. Nothing more than 5-10 Mins tops.