Every time you place pre-loved clothes in Shwop boxes, they're resold, reused or recycled through Oxfam so absolutely nothing goes to waste.
What's more, if you're a Sparks cardholder, you'll get a free treat every time you Shwop. Simply scan the QR code on the top of the Shwop box in any M&S clothing store and the treat will appear in your Sparks hub.