Experts share advice on combating musty laundry smell

Australia Broadcast Center

01-08-2025

Part way through folding your freshly washed — and now dried — laundry, you notice it.
You catch a whiff of that sour, musty, mildew funk. It's all through your washing.
Have you ever wondered what causes that dreaded smell and what you can do to tackle it? We asked some experts. This was what they had to say.
Nathan Kilah, a senior lecturer in chemistry at the University of Tasmania in Lutruwita, says "musty smells are caused by microbes".
Microbes can reproduce in damp or soiled clothing, where they can create microbial volatile organic compounds (or MVOCs), Dr Kilah says.
"[These compounds] have certain characteristic smells that we can pick up at quite low thresholds" as "we're very sensitive to smelling them".
It can present as a rotting or sour smell, Dr Kilah says, and your washing is most at risk when it's left in a washing machine or in a washing basket.
"If [it's] wet then that will be the perfect environment for microbes to grow."
Warm weather can help the microbes along, he says, and so it's likely to be a more pronounced problem during summer or if you live somewhere hot.
Maryam Naebe, who researches fibre science and technology at Deakin University on Wadawurrung country, she says some fibres are more likely to retain odour than others.
Dr Naebe says wool is less likely to be an offender because of its structure, but polyester — which repels water and traps body oil — is an alluring candidate for MVOCs.
And cotton "takes a long time to dry", giving microbes "more chance to grow".
To get rid of the smell, textile expert Rebecca Van Amber says washing the offending laundry is critical.
A senior lecturer at the School of Fashion and Textiles at RMIT University in Naarm/Melbourne, she says: "There's no way to get rid of that musty smell except to wash them again."
She finds adding a bit borax powder can help, "especially for towels", and says putting a tablespoon of white vinegar in the fabric softener drawer is "really useful for getting rid of bad smells".
Dr Kilah says vinegar is often recommended for combating smelly washes or machines, but he advises checking the manufacturer's instructions for your machine first.
Dr Van Amber says if you really want to avoid rewashing, you can try hanging things outside in the sun, which may help reduce the odour.
When it comes to avoiding the issue altogether, Dr Kilah says "ventilation is number one".
He recommends emptying the washing machine and hanging up your load as soon as possible: "Get them out and get them dry."
Dr Naebe says ensure your laundry dries completely, particularly in humid conditions.
Dr Kilah says the cleanliness of your washing machine can also be a factor.
The different soaps and products we add to our washing machines can leave behind a residue that can enable microbes to form a biofilm.
"They sort of grow and inhabit the surfaces of the washing machine," he says.
It's more likely to be an issue if you use fabric softeners (as they leave more residue behind), only cold wash or only use liquid detergents.
"Cold-cycle washes are less likely to kill the microbes", according to Dr Kilah, and many powdered detergents contain "a peroxide source which is able to actually kill some of the microbes."
He recommends running a hot wash cycle occasionally and says switching to a powdered detergent may help battle a persistent laundry odour.
Products designed to clean washing machines can also help "dissolve soap scum", but he advises only using them about every three months.
Unpleasant-smelling laundry might have you reaching for scented laundry detergents and fabric softeners but Dr Kilah says that while they might mask the smell, they won't tackle the underlying cause.
Scents and perfumes come down to personal preference, Dr Van Amber says, "but a lot of people are actually really sensitive to these strong smells".
A strongly scented laundry detergent may be just as offensive as a musty smell, and "it can actually make some of the smells worse".