Sweat-stained running shoes, double-pluggers that have blown out, work boots that smell so bad they could kill a cat at 20 paces.
They're pure gold to recyclers and Australians are being urged to surrender them to mark Global Recycling Day on Saturday.
As the nation transitions to a circular economy, more and more niche recycling programs are popping up and shoes are no exception.
The TreadLightly program, backed by the Australian Sporting Goods Association and recycler Save Our Soles, has already recycled more than 600,000 pairs of shoes.
But that's a drop in the ocean, with the association saying 25 million sports shoes are imported into Australia every year.
Executive director Shaun Bajada says Australians should know eligible shoes - including most sports shoes, school shoes, thongs, slides and even gumboots, can be remade into new products including gym mats and flooring.
"Shoes can be recycled, no matter how dirty or over-worn they are."
A network of retailers across Australia act as collection points for old shoes, which are then sent to Save our Soles, which shreds them.
Various components such as metals and textile fluff are extracted and separated, with shoe waste blended with rubber from recycled tyres to make new products.
Save our Soles says all material is collected, recycled and manufactured in Australia.
For drop off locations check the TreadLightly website.
