Vinegar beats baking soda for lunch box stink.

White vinegar and a good air-out will fix a lunch box that smells like onions or fish — soap alone won’t.

Plastic is porous. The stink gets into the material, and dish soap just leaves a film of fragrance over the top. By Thursday the “lemon fresh” scent is gone and you’re back to smelling Friday’s tuna.

Here’s the fix: wipe the inside with undiluted white vinegar, let it sit for ten minutes, then rinse and dry it with the lid open. Vinegar neutralizes the amine compounds in fish and the sulfur compounds in onions. It smells like vinegar for a bit, but that fades way faster than fish.

For prevention, the bigger win is not letting the smell set in. Keep onion-heavy stuff and fish in a small glass container inside the lunch box — glass doesn’t absorb odors like plastic. And never seal the box while it’s still warm. Heat pushes the smell into the plastic.

This is not where you save six bucks. Get a cheap glass container for the smelly stuff.