A forgotten sock, a scoop of baking soda and a little chemistry: what this old trick can and cannot do. Open the cabinet under the kitchen or bathroom sink, and you may be greeted by a stale, slightly musty smell. It is one of the most common household complaints, and one of the oldest fixes is still passed down from generation to generation.
Fill an old sock with baking soda, tie it closed and leave it under the sink. Grandmothers swore by it. Chemistry explains why it can help, and where it falls short.
How Baking Soda Fights Odors
Baking soda, or sodium bicarbonate, is often described as absorbing smells. That is not quite accurate. It neutralizes certain odor molecules through a chemical reaction. Baking soda is amphoteric, meaning it can react with both acidic and basic compounds. When an acidic or basic odor molecule meets it, the reaction changes the molecule so it no longer smells the same.
Anthony Rojas, a chemist and senior academic professional in the School of Chemistry and Biochemistry at Georgia Tech, explains that baking soda does not work by absorbing odors, and that the neutralization “actually happens outside the box.”
Why Contact Is Everything
That detail matters. For baking soda to work, odor molecules have to reach it. In an enclosed, still space like a sink cabinet, a sock full of baking soda can catch some of those molecules. But it will not clear the air in a large or ventilated space.
Food chemist Robert Wolke has argued that no single chemical can neutralize all the complex gases that cause bad smells. In a test by America’s Test Kitchen, an open box of baking soda left overnight with spoiled foods produced inconclusive results. Baking soda worked best when it touched the smelly surface directly, for example as a paste scrubbed on a cutting board.
What It Cannot Do
Baking soda is not a dehumidifier. It will not dry out a damp cabinet in any meaningful way, and it will not stop mold.
And a musty smell under the sink is often a warning sign. It can point to a slow leak from a pipe, a loose fitting or a worn seal, which allows moisture and mold to build up. Before trying any trick, check the pipes, the base of the cabinet and the back wall for dampness, stains or soft wood. If you find water, fix the source first.
How to Use the Sock Trick Properly
Choose a clean, breathable cotton sock and fill it with half a cup to a cup of baking soda. Tie it securely or close it with a rubber band. Place it in the back of the cabinet, away from anything wet.
For better contact, spread the baking soda in a shallow open dish instead, so more surface is exposed. Replace it every one to three months, or sooner if the smell returns.
A Fresher Cabinet in Four Steps
Empty the cabinet and wipe it with warm, soapy water. Let it dry completely with the doors open. Check for leaks. Then add your baking soda sock or dish and keep products tightly closed.
Goodbye musty cabinet smell. The old-sock trick grandmothers swore by does have chemistry on its side, as long as you treat it as a finishing touch, not a cure for hidden moisture.
