How to reliably remove that musty damp smell from clothes
A shirt I’d washed and sun-dried smelled like a damp rag as soon as I sweat in it. I’d stored it clean in the drawer. Worse, it was a quick-dry shirt—yet still got musty. You sometimes catch this smell on rainy days; it ruins the mood, so I wanted a sure fix.
How to remove the musty smell
This article had everything—“Sekken Hyakka” (soap encyclopedia) usually solves laundry questions:
Musty clothing odor removal (Sekken Hyakka, JP)
Five methods are listed, which boil down to heat or chemicals.
Heat methods
- Boil wash
- Clothes dryer
- Boiling-hot water dip
- Ironing to disinfect
Chemical method
- Oxygen bleach (sodium percarbonate) soak
The smell is leftover grime plus bacteria. Kill the bacteria with heat or chemicals and the smell stops.
I’ve tried boiling-hot water and oxygen bleach and both worked. Boiling, dryer, and iron sounded tedious or I lacked the gear. The “seaweed” photo above is a soak in oxygen bleach + warm water.
Sekken Hyakka leans “natural,” so you could add “soak in oxygen bleach like Wide Haiter” or “chlorine bleach (will whiten).”
Which is easiest?
Oxygen bleach soak wins. It’s the common ¥300-ish box at drugstores:
Fill a tub with warm water, dissolve some powder, and drop in the smelly clothes. Officially an hour is enough; it’s gentle enough to leave longer. Most offenders are underwear/quick-dry shirts—not expensive—so I’m casual about it.
Water temp: 40–50°C is best. The shower safety stop sits around 40°C, so I use that. Dose by feel until the water feels slightly slick.
Despite the “bleach” name, it’s safe on colored items.
What is oxygen bleach?
A stronger alkali than baking soda or sesqui washing soda, yet still mild as detergents go—hence the forgiving use. It can replace synthetic detergents in “natural” laundry and is blended into “whitening” detergents.
When mixed with hot water it cleans two ways: bleaching from the reaction, and degreasing from the alkaline state afterward. Details (JP):
Washing with sodium percarbonate (oxygen bleach) – Sekken Hyakka
“No wool/silk/metal trim/plant-dyed items.” Those are usually handwashed gently or dry-cleaned anyway; for everyday clothes, alkali is fine.
Also cleans the washer drum
Fill the washer with hot water and oxygen bleach, let it sit, and wakame-like gunk can float up from the back of the drum. Reviews have gnarly photos:
Amazon review with drum grime (JP)
My washer is new-ish, so not much came out:
Adding a bit to regular detergent also cleans the machine over time—two birds with one stone.
Our usual laundry routine
We don’t get heavy stains, so we use the washer’s quick mode with NANOX, adding Wide Haiter when white shirts yellow. That works, but quick-dry sports shirts trap a lot of sweat and got funky this time.
I could have soaked them in NANOX/Wide Haiter, but modern liquids are tiny and I felt stingy, so I sought another option. Oxygen bleach is ~1 kg for ¥350–400—easy on the wallet.
This also rescues indoor-dried clothes that smell; same root cause (residue + bacteria), same fix.
Summary
- If clothes stink, soak in oxygen bleach + ~40°C water.
- Add a little to regular loads for ongoing benefits.
- See Sekken Hyakka and Amazon reviews for more.
Previously I used this on bath towels too:
