Post your "Good News" stuff here. Typically, microwaves agitate polar molecules (molecules that have magnetic properties), like water, into very rapid motion. The collisions between these rapidly moving molecules create frictional heat, first within the liquid water, which is then transferred to the entire food or beverage contents. Since polystyrene foam cups or containers themselves do not contain water within their molecular structure, they are "transparent" to the microwaves. The microwaves pass right through, and the container is unaffected. If the container’s temperature changes, it’s only because of the increasing heat of the liquid or solid they contain. The part about foam cups being safe in the microwave is of particular note. I was not certain but thanks to this data I am relatively at ease. I use them for hot cocoa.