Don't trust the label — trust the symbol

Most lunch containers marked with a microwave-safe symbol are fine to reheat in the office, but glass and ceramic are always the safest bet.

Flip the box and look for the little microwave icon (wavy lines) or the words “microwave safe.” If it’s plastic with recycling code #5 (polypropylene), you’re usually good. Codes #1, #2, and #4 are also generally fine if the container says microwave-safe. Avoid #3, #6, and #7 unless it’s explicitly labeled — that’s where you get the mystery chemicals.

Styrofoam (#6) is the big one. That stuff doesn’t belong in any office microwave. And metal? Not even a little foil edge on the lid. That’s a spark show.

One more office-real-world tip: scratched, warped, or stained plastic has done its service. Transfer it to a mug or paper plate instead. And please cover the bowl so someone’s soup doesn’t redecorate the microwave.

When in doubt, put it on a ceramic plate and nuke it there. Your lunch will taste the same, and you won’t be the person who set off the office alarm.