EVER wondered what happens if you wear the same pair of jeans five days a week for three months straight without washing them?

Melbourne researcher Tullia Jack recruited 30 volunteers to do just that - and will soon exhibit the grimy garments at the NGV so the public can put them to the pong test.

She hopes the unusual experiment for her Master of Philosophy thesis will challenge our culture of "extreme clean".

Despite stains and spills ranging from tuna and avocado to motor oil and chocolate, Ms Jack says the expectation dirty denim will be whiffy is much worse than the reality.

"Not washing your jeans isn't nearly as bad as it sounds," the Melbourne University student and RMIT fashion lecturer says.

"You really don't need to wash clothes as often as you think. Stains come and go, they just wear off."

Burying her nose in the pile of well-worn jeans on her desk, she picks out perfumes ranging from eggshells to caramel.

"The jeans don't smell socially challenging. They just smell like people," she says.

Only one of the 30 experiment participants struggled to complete the task, which involved wearing a pair of duds donated by local denim label Nobody at least five days a week in March, April and May this year.

Many chose to expand the experiment and stopped washing other garments in their wardrobe such as T-shirts, shirts and jumpers, Ms Jack says.

The sustainable fashion advocate said participants had collectively saved thousands of litres of water, and had also saved on electricity and soap powders.

She hopes her Nobody was Dirty exhibition, where the public will be invited to sniff the used jeans at the NGV Studio in March, will motivate many more Victorians to launder less.

Participants were recruited on social media. They ranged in age from 18 to 56, with an even split of men and women. They included a librarian, a high school teacher, a festival producer and a graphic designer.

The "great unwashed" kept Facebook diaries and were regularly interviewed to see how they felt - and smelt.

About half hit a rough patch between the three and six-week mark, and reported they didn't want to wear the jeans any more, Ms Jack said.

But by the time the experiment ended, half wanted to continue wearing - and not washing - their dirty jeans.

Ms Jack's research found men were more likely to wash inner layers more frequently, and were more conscious of their scent.

"I thought the boys would be smellier, but they weren't," she said.

One participant, Matthew, told the Herald Sun the jeans experiment had made his life much easier.

"I didn't have to work out what to wear every day," he said.

hudsonf@heraldsun.com.au

Originally published as The great dirty jeans smell experiment