I heated some coffee this morning in a plastic coffee cup - the ones with a lid that turns so you can drink it in the car, this had no visible metal on it so I figured it would be ok. About 45 seconds in I saw flames, opened the microwave door and the cup was on fire. I managed to put it out with a cloth, nice stinky kitchen and I now have a sooty microwave. I got some of the soot off with a damp cloth but the inside has soot stuck onto the sides.
Is the microwave useable now, is it dangerous and will the soot come off in time with moisture and wiping, or do I just dump it and replace it? Fortunately it's not a built in microwave just a counter top one so easy enough to replace for about $80 or so.