Onions, the timeless aromatic used to fragrance dishes in all cuisines, leaves you with something you don't soon forget: its timeless odor. Every plant in the allium family -- garlic, onions and shallots, to name a few -- get their pungency and telltale aroma from sulfenic acids. When sliced, torn or crushed, alliums' cell walls release allinases, which convert sulfenic acids to the less-than-desirable odor that permeates the interior of plastic food-storage containers. You have to battle the dreaded onion smell with equal firepower: a cleanup plan that starts organic, and, if necessary, moves on to the big guns -- all-purpose bleach.
Mix 2 parts baking soda and 1 part lemon juice together. Coat the inside of the container and the bottom of the lid with the paste. Add more lemon juice if needed to loosen the paste.
Let the container sit for 48 hours; then wash it. Check for any additional odor. If you still detect an onion smell, mix together 1 capful of all-purpose bleach with 1 quart of water.
Pour the bleach water in the container and seal. Shake the container and let it sit for 12 hours; then rinse.
Place a piece of charcoal in a smelly food container and let it sit, covered, for 24 hours. Activated charcoal is a natural odor absorber, but its ability to absorb is limited by its size.