Charities want consumers to think twice before making an impulse buy at a fast fashion store after new figures reveal it is costing millions of dollars to send unusable donations of cheap clothing to landfill.

Key points: Charities are paying $13 million a year to send unusable donations to landfill

Charities are paying $13 million a year to send unusable donations to landfill Poor-quality 'fast fashion' reportedly a significant contributor to problem

Poor-quality 'fast fashion' reportedly a significant contributor to problem Charities finding innovative ways to repurpose items destined for landfill

"If you wouldn't lend it to a friend, or give it to a friend … don't donate it," Omer Soker from the National Association of Charitable Recycling Organisations (NACRO) said.

Cheap, mass-produced clothes are often in no shape to be handed down so Australian charities are forced to dispose of them and new figures reveal that is having a devastating impact on their budgets.

Australian charitable recycling organisations are spending a staggering $13 million per year sending unusable donations to landfill.

"There is a phenomenal amount of stuff and a lot of that is garments [and] textiles," Mr Soker said.

"If it was all quality stuff, that would be one thing, but a lot of it is fast fashion. Fast fashion has no intrinsic value in the fibres; it's not designed to last.

"It really should be called fast-to-landfill fashion, because ultimately that's what it is."

As well as worn-out clothes, charities report having to dispose of soiled mattresses, broken appliances and even dirty nappies.

Mr Soker said the charities were having to send about 60,000 tonnes of unwanted items to landfill every year.

"All of this stuff comes from donations that either have no value at all, or can't be used. It's a really big burden on charities," he said.

A Vinnies donation bin at Glebe Point Road in Sydney is a notorious spot for dumping. ( ABC News: Penny Timms )

Often those unusable items litter the footpath outside charities or the area around donation bins so organisations have no choice but to spend money cleaning up.

Mr Soker said that money would be better spent on the charitable cause, including "emergency food, shelter, aged care, mental health and suicide counselling".

Dumping bill prompts innovation at major charities

The Salvation Army spends a portion of its budget on disposing of donations that are not of any use. ( ABC News: Penny Timms )

A charity bin in Melbourne displays a warning against illegal dumping. ( ABC News: Amy Bainbridge )

Some charities are working to turn trash into treasure, launching innovative projects designed to salvage some items that would otherwise be sent to landfill.

For running enthusiast Graham Ross it was a growing pile of smelly sports t-shirts that prompted a career change and the launch of a major recycling pilot project with the Salvation Army.

"I did a bit of research and I discovered my wardrobe is full of polyester, cotton, spandex and nylon, like most people," he said.

Mr Ross started researching sustainable fibres and initially developed a t-shift that used just 1 per cent of the usual 3,000 litres of water during manufacturing.

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Before long, Mr Ross was looking at the bigger picture and launched start-up Blocktexx with the goal of recycling existing clothing.

In his project with Salvation Army, Mr Ross and his business partner Adrian Jones have developed a hand-held scanner that can quickly identify the composition of a donated garment.

It's the first step in developing a streamlined sorting process that would separate donated clothes into fabric types ahead of recycling.

"I approached the Salvos to say, 'If you give me some discarded clothes, we'll take them away and shred them, then spin them into a fibre and turn them into a fabric'," he said.

"The end goal would be to turn that into a garment they hypothetically could sell back in their stores."

Once the fibre in a garment is identified, it can be sent to a recycling facility which breaks down the fabric.

Cotton can be broken down mechanically, while fabrics like polyester use a chemical process to break down.

"Polyester can take somewhere between 20 and 200 years to break down, and while that's happening, it's emitting all sorts of nasty chemicals," Mr Ross said.

"So it's also incredibly versatile. We can use it multiple times at a high grade, but also we can keep reusing it and reusing it as it degrades into lower-value products."

Textiles donated to Australian charities are often destined for landfill. ( ABC News: Amy Bainbridge )

Technology aims to take textiles out of landfill

Blocktexx co-founder Mr Jones said the goal was to create a fashion technology platform and marketplace for recycled fibres.

"We would really like to see over the probable [next] three to five years that we can take tens of thousands of tonnes of textiles out of landfill," he said.

"Instead of just hoping that somebody buys them [the donated clothing] or hoping that if we store them, the problem will go away, [we want to] convert that problem.

"That textile waste [becomes] a textile resource that retailers, consumers, government can all use to make more sustainable clothing."

Blocktexx scans donated textiles and identifies the fabric, making sorting ahead of recycling easier. ( ABC News: Amy Bainbridge )

Vinnies stores have a goal to be waste and landfill-free by 2023 and a social enterprise project in New South Wales is helping move the operation close to that target.

In the small town of Coonamble, workers turn recycled jeans and textiles into shopping bags.

The bags are made by workers from Castlereagh Industries, which is part of the St Vincent de Paul Society and they are supported by employees who have a disability.

"The whole purpose of what we're doing is to provide employment for persons with a disability, plus the education, and training," Vinnies strategic project manager Megan Sprague said.