Turns out, it’s pretty complicated. Most textiles are recycled in one of two ways: mechanically or chemically. Mechanical recycling is the most common method, with 12 per cent of clothes recycled this way. It involves a bunch of machines shredding and carding (detangling) fabric to create short, weak fibres. Due to their quality, these fibres are usually downgraded to make things like rags, insulation, carpet and mattress stuffing. Mechanical recycling works best for natural, single fibre fabrics like cotton or wool.   

Less than 1 per cent of textiles are chemically recycled back into reusable material, a process known as fibre-to-fibre recycling. It requires sophisticated (and expensive) tech that extracts raw materials from fabrics with no quality loss. Cotton, for example, can be broken down into cellulose pulp which is then spun into new cotton fibres.   

The process also works for blended fabrics, with solvents used to melt materials down into their component parts. This means you can take a poly-cotton shirt and turn it into PET plastic and cellulose. Any dyes present on the fabric are dissolved using a separate chemical process and buttons, zips and the like are removed mechanically.   

While there is some exciting chemical recycling tech emerging, uptake has been slow due to the cost associated with scaling these systems. BlockTexx is a textiles recycling technology that turns poly-cotton waste into high-quality PET and cellulose. Another promising innovation is NuCycl, a fibre made from 100 per cent post-consumer textiles waste that “can be disassembled to the molecular level and regenerated multiple times into new clothing, home and industrial textiles”.   

Renewcell is also one to watch. This year it will ramp up production of Circulose – a material made from recycled cotton that has been trialled by Levi’s, H&M and Ganni – with the opening of a new plant capable of producing 120,000 tonnes of fabric per year (the equivalent of over half a billion T-shirts).   

The sheer complexity of garments presents major recycling challenges. Take a pair of work pants – buttons, zips, stitching, dyes and blended fabric all need to be dealt with separately. Then there’s the issue of quality loss, especially as a result of mechanical processes that weaken fibres. For this reason, recycled and virgin fibres are often mixed to create a stronger material (which kinda defeats the purpose of recycling in the first place).   

To make things even trickier, there are a few crucial steps that need to happen before clothes even make it to a recycling facility. The first one is collection and the second is sorting.   

Collection is largely the remit of governments who must establish accessible systems to capture textile waste. This is already underway in France, where a mandatory extended producer responsibility law for textiles has been implemented. Under the law, producers are required to collect and process their own waste. To facilitate this, 44,000 drop-off points for used textiles and footwear have been set up across the country.   

Sorting collected clothing into fabric types is a critical part of the recycling process and, currently, it’s done by hand. This is a painfully slow procedure that’s vulnerable to human error, particularly when material labels have been removed. But luckily, artificial intelligence and the internet of things have the potential to revolutionise sorting with smart devices like Sortile, a technology that uses near-infrared spectroscopy and machine learning to identify fibre composition. (We have no idea what that means either, but it sounds great.)  

Lack of access to recycled textiles means brands are forced to source waste materials for recycled products from other industries. This means, rather than creating circular solutions for textiles, recycled materials are simply being fed into the same old linear fashion system. To get a better understanding of the implications of this, let’s take a look at one of the most popular recycled fabrics: polyester.   

Roughly 95 per cent of recycled polyester comes from PET plastic bottles. This might seem like a good thing on the surface – it’s diverting waste from landfill, right? But with no end-of-life solution in place for those recycled leggings, brands are inadvertently creating a new waste problem.  

“If you’re using PET bottles, you’re breaking this closed-loop system [as] it’s really easy to recycle bottles to bottles,” Philippa Grogan, sustainability consultant at Eco-Age, tells British Vogue. “Recycled polyester is really hard to recycle [again].”