Via SciTechDaily, a story in The Atlantic about a unique recycling project: turning discarded Christmas lights into slippers. Yong Chang Processing, in Shijiao, China, recycles around 2.2 million pounds of Christmas lights each year. The original plan was to extract the copper, but soon a market developed for the wiring’s insulation, which is used as the raw material for a variety of products, including slipper soles.

Workers untangle the lights and toss them into small shredders, where they are chopped into millimeter-sized fragments and mixed with water into a sticky mud-like substance. Next, they're shoveled onto a large, downward-angled, vibrating table, covered in a thin sheen of flowing water. As the table shakes, the heavier flecks of copper (from the wire) and brass (from the light bulb sockets) flow in one direction, and the lighter plastic and glass (from the insulation and bulbs) flows in another. It's the same concept that miners use when panning for gold, and the results of this updated, age-old technology can be found at the far end of the water tables: baskets of roughly 95% pure copper and brass alongside baskets of insulation and glass. The contaminated water, meanwhile, flows into a recovery system, where it's re-circulated, over and over, through the recycling system.

So when you toss out your Christmas lights into the recycling bin, chances are they will be sold to China—and you may end up getting it all back if you buy slippers or other Chinese-manufactured products. The question, though, is: if the sole of one slipper wears out, will the other stop working?