Microwave the food, not the lid

Get glass with a plastic lid, and take the lid off before you microwave.

The freezer-to-microwave trick comes down to two materials doing two jobs. Glass is the body — it handles the cold-to-hot swing without warping, staining, or holding onto last week’s curry. Plastic is for the lid, because a glass lid is heavy and harder to seal. The catch: most plastic lids are not actually microwave-safe, or they’ll warp from steam pressure the first time you blast them. That’s why nearly every brand says “remove lid before reheating.” Freeze with the lid on, heat with it off or just cracked, and you’re fine.

If you’re buying new, look for borosilicate glass. It’s lab-beaker material and it shrugs off thermal shock. IKEA’s 365+ line is borosilicate and cheap. US Pyrex is tempered soda-lime glass, which works, but let it sit on the counter for five minutes before nuking so you’re not shocking it straight from the freezer. Either way, wide and shallow beats deep — food reheats evenly instead of getting a lava center