Dry it upside down with the lid open.

The best way to dry a lunch box is to take it apart, towel it off, and let it air dry upside down with the lid open.

Mildew needs trapped moisture, and lunch boxes are full of hiding spots. The rubber gasket or seal is the biggest offender — it holds water even when the box looks dry. Same with hinge gaps and any removable dividers. If you skip those, you’ll get that faint musty smell and eventually black specks.

So unclip the gasket if you can, pull out any inserts, and give the whole thing a shake and a quick wipe with a dish towel. Then prop the box upside down on a dish rack or a towel with the lid open. Gravity does the work, and airflow does the rest. If you’re in a hurry, point a fan at it or set it near an open window. Just don’t snap it shut and put it away until every surface is bone dry.

My rule: if it still feels cool or damp to the touch, it’s not ready to store. Leave it out overnight and the problem basically disappears.

Future you won’t be scrubbing pink mold out of the hinge.