Dry the gasket or you'll be scrubbing mold.

Clean the rubber seal with warm soapy water after every use, but the real trick is letting it dry completely before you snap the lid shut.

The seal traps moisture. If you close a damp gasket into a dark box, you’ve built an incubator. Pull the seal out if it’s removable (most are), wash it with dish soap, and leave it on the drying rack. If you’ve already got mold spots, soak the seal in a 50/50 white vinegar and water mix for 15 minutes, then scrub with an old toothbrush. Baking soda paste works too. Rinse well.

The biggest mistake is putting the lid on while the seal is still wet. I get it — you’re in a hurry. But that’s what turns a tiny rubber strip into a science experiment. Air dry is non-negotiable.

A few extra minutes of drying saves you from eating lunch out of a container that smells like a basement.