Cotton not only accounts for roughly a third of the world’s textile consumption but is also in danger of becoming a scarce resource as the world’s increasing population needs more land for food production. European brands have taken to making garments made entirely from recycled cotton. The technology allows them to recycle all materials that contain cellulose.

Old cotton clothes are brought to a factory and shredded and then turned into a porridge-like substance. After non-recyclable pieces like zippers and buttons have been removed, the porridge is broken down to the molecule level and turned into a fiber substance to be used for thread, resulting in rayon fabric. It is possible to recycle fabrics that contain a mix of cotton and other materials but the best results are got when recycling pure cotton.

From a sustainability perspective, cotton recycling scores particularly well as it uses no new ingredients other than timber, whose cellulose fibers can be added to the existing cotton ones.

But recycling of fabric often involves dangerous materials such as heavy metals. And because rayon is much harder to recycle than cotton, the recycling doesn’t go full circle. A better approach would be to compost the clothes. Valuable nutrients could be added to clothes, which would benefit the soil when they are composted.