Baking soda fixes lunch box smells and tomato stains.

The fastest fix is baking soda: make a paste for tomato stains, and leave an open box of it inside the empty lunch box to kill odors.

For tomato sauce specifically, rinse out the loose stuff with warm water, then scrub with a dab of dish soap — you need that to cut the grease, not just the red color. Rinse again and make a thick paste with baking soda and water. Rub it into the stained plastic, let it sit for ten minutes, then wipe and rinse. If the stain is older, repeat once. That usually does it.

For lingering smells, wash normally, dry completely, then let an open container of baking soda or a crumpled newspaper sit inside overnight with the lid cracked. The sun is the real winner though: set the lunch box in direct sunlight for an hour and any odor that’s left will die. UV light is a surprisingly good deodorizer, and it costs nothing.

Don’t seal the lid shut before it’s fully dry — that’s how odors set in and stick around for months.