Baking soda and sunlight solve smelly lunch boxes.

Baking soda and sunlight will get almost any smell out of a plastic lunch box.

Plastic is porous, and once tomato sauce, curry, or garlic get into the scratches, they don’t wash out with regular soap. That’s why the smell keeps coming back.

Option one: make a paste with three parts baking soda and one part water. Coat the inside, leave it overnight, then scrub and rinse. Option two (faster): soak in a half-vinegar, half-water mix for a few hours, then wash. Do not use boiling water; it can warp some plastics or bake the smell in deeper.

The step everyone skips: put the box in direct sunlight for a few hours. UV light breaks down odor molecules and kills the bacteria producing them. If you only do one thing, do this.

If the smell survives that, the plastic is done. Toss it and get a glass one — glass doesn’t do this.