How to Get the Mildew Smell Out of Towels (and Keep It Out)

Why towels start to smell like mildew

To get the mildew smell out of towels, it helps to know where it comes from. The sour, musty odor is made by bacteria and mildew that grow when a towel stays damp for too long. Thick cotton loops hold a lot of water, so a towel bunched on a hook, left in a gym bag or forgotten in the washer can start to smell within hours.

Residue makes it worse. Too much detergent, and almost any fabric softener, leaves a film on the fibers. That film traps moisture and odor, so the smell comes back as soon as the towel gets wet again. A front-load washer with a damp door seal can add its own musty smell to every load.

How to get the mildew smell out of towels, step by step

First, wash the towels on the hottest setting the care label allows, with one to two cups of white vinegar and no detergent. The vinegar breaks down the residue and the odor that lives in it.

Second, run a second hot cycle with about half a cup of baking soda, again without detergent. Baking soda neutralizes what the vinegar loosened and leaves the fibers clean.

Third, dry the towels completely, right away. Use high heat in the dryer, or hang them flat in the sun. A towel that comes out of the dryer still a little damp in the middle will smell again by the next day.

Then do the smell test on a dry towel. If a faint odor is still there, repeat the two cycles once. Never mix vinegar and chlorine bleach in the same wash: together they release a harmful gas.

If the smell comes back after one use

If towels smell fine out of the dryer but sour after one shower, the problem is usually build-up in the fibers or in the machine. Cut detergent back to the amount the label recommends for the load size, and stop using fabric softener on towels. It coats the loops, makes towels less absorbent and holds on to odor.

Clean the washer too. Run an empty hot cycle with vinegar or a washer cleaner, wipe the door seal and the detergent drawer, and leave the door open between loads so the drum can dry.

How to keep towels from smelling

Most mildew smell is prevented in the hours after a towel is used. Hang towels spread out, not folded or bunched, so air reaches both sides. Don't leave wet towels in a hamper, a bag or the washer overnight, and wash them within a day or two.

Don't overload the machine, because towels need room to rinse. And never fold or store a towel until it is completely dry, all the way through the thickest part.

Why hotel towels smell fresh

Hotels wash far more towels than a home, in far wetter conditions, and they still have to hand guests a towel that smells clean. The difference is process. A commercial laundry doses chemistry by the load instead of by guesswork, washes at the right temperature, extracts water at high speed and tumbles towels until they are fully dry.

Time matters just as much. In humid places like South Florida, the biggest risk is wet towels sitting in bags overnight before they are washed. Hotels that get soiled linen out of the building quickly, on a regular pickup schedule, rarely fight mildew at all. Pool and spa towels, which carry sunscreen and body oils, are best washed as their own load with their own treatment.

When a towel can't be saved

If a towel still smells after two rounds of vinegar and baking soda, or it has turned gray, stiff and thin, the fibers are worn out. At that point it costs more in water, energy and guest complaints than it is worth. Retire it to cleaning rags and replace it.