Microwaves are a convenient and energy-efficient way to cook and heat up leftovers instead of using the oven. But when using a microwave, opt for only microwave-safe glass or ceramic containers, even if a plastic container is marked "microwave-safe." That marking on plastics means they can withstand heat up to a certain temperature; if you're cooking something on high for an extended period of time, even microwave-safe plastic containers can lose their shape and could leach chemicals into your food.
ANDREWS MCMEEL SYNDICATION