Six Microwave Safety Mistakes to Avoid

Some plastics contain chemicals, such as BPA, that can leach into food when heated, so unless the container is labeled microwave-safe, leftovers are better transferred to a glass container or plate first.

Low-fired ceramics can retain some of clay's porous nature and soak up moisture, which can heat up inside a microwave and potentially crack the dish; glass is the safer bet when in doubt.

Packaging should only go in the microwave if it specifically says so, and even then it should be discarded afterward, with holes poked to let steam escape during heating.

A kitchen sponge can be disinfected in the microwave, but only if it's thoroughly wet first — a dry sponge can quickly catch fire.

Very clean water in a very clean container can become superheated without showing visible signs of boiling, then release that stored heat violently when disturbed; placing a wooden spoon or stir stick in the water while heating helps prevent it.

Without food or liquid inside to absorb the microwaves, the magnetron absorbs them instead and can be damaged, so a few seconds of accidental empty-running is worth avoiding.