The real fix for a smelly lunch box is a baking soda paste.

The best deodorizer for a smelly lunch box is a paste of baking soda and water, and the best prevention is washing it right after you finish lunch.

Plastic lunch boxes soak up odors from anything strong — fish, curry, onions, whatever you ate days ago. Soap and water mostly just spread it around. Baking soda actually pulls the smell out because it’s a mild alkali that neutralizes odor-causing acids. Coat the inside with the paste, leave it overnight, rinse the next morning. Done.

For extra-stubborn smells, white vinegar is your fallback. Wipe the inside with vinegar, let it sit for a few minutes, then wash normally. The vinegar smell goes away as it dries, and it takes the old food smells with it.

To prevent the problem in the first place: don’t leave the box sealed shut all day with trapped moisture. Air it out after lunch, and wash it as soon as you get home. And if you’re packing something like tuna or curry, put it in a separate container instead of letting it touch the bare plastic.

Your next lunch shouldn’t taste like your last one.