My entire life I have always been heating tea and coffee in styrofoam cups in the microwave for 2 minutes and never had a problem. But then last week I had some left over food on a styrofoam plate which I heated for 2 minutes and the styrofoam melted completely and burned up.

This is when a lightbulb when off in my chicken head... that perhaps styrofoam is not suposed to be put into a microwave? I cannot believe I didn't know this until now!

But I thought you could put those styrofoam cups you buy at the grocery store into the microwave... those cups have NEVER melted.. but the styrofoam plate I got from the restaurant melted almost instantly in the microwave. That makes no sense.

Are some styrofoam cups/plates micowavable and others are not?