Soak it in vinegar, then put it in the sun

Vinegar works, baking soda is okay, lemon is more of a nice idea than a fix — but sunlight does the heavy lifting.

Start with a normal wash in hot, soapy water. That gets the grease off. Then soak the whole container in white vinegar, straight or mixed with equal parts water, for 15–20 minutes. Vinegar is a mild acid, so it breaks down the film that holds the smell and kills a decent amount of mold and bacteria. Rinse it well.

If the smell is still hanging around after that, make a thick paste of baking soda and water, coat the inside, and let it sit for an hour before scrubbing and rinsing. Baking soda is better at absorbing odors than killing them, so it works best as step two, not step one. Lemon juice has citric acid, which helps a bit, but it’s not stronger than vinegar and it can leave a sticky residue, so skip it unless you’re out of vinegar.

One more thing: let the box dry completely before you close the lid. Moisture is what makes it smell again. If you can set it in direct sunlight for an hour, do that — UV kills the stuff vinegar misses and really knocks out plastic odors. The whole routine is about ten minutes of actual effort.