Look for the microwave-safe symbol before you trust that lunch box

Yes, some lunch boxes are safe to microwave without taking the food out—but only if they’re actually made for it. Don’t assume. Check the bottom for a microwave-safe symbol or label.

Most everyday plastic lunch boxes aren’t safe. Cheap plastic can warp, melt, or leach chemicals into food. The safe materials are glass, ceramic, and certain plastics (generally #5 polypropylene). Silicone is also fine. You’ll see it clearly marked.

The tricky part is lids and compartments. A container might be microwave-safe, but its lid might not be—or it might be too tight and explode the food everywhere. Vent the lid, or just take it off. Also, if there’s any metal trim, hinge, or handle, it goes in the microwave only if you’re trying to start a fire. You aren’t.

Bento boxes are the worst offenders. They look practical, but many are made of acrylic or melamine, which are not microwave-safe. Even safe ones often have a silicone seal you have to remove first. So read the packaging before you buy, not just the symbol.

When in doubt, transfer it to a plate. That’s what plates are for.