If you’re about to crush an aluminum can like a beast and recycle it in good conscience – stop and do a quick online search of your local facilities. It is possible that smashing your can to save space is not the good deed you believe it to be.

Turns out, not all recycling facilities can handle crushed aluminum cans as well as others. For some facilities, crushing cans is helpful and conserves room for more. For others, the cans fall through the cracks and get mixed into the wrong recycling stream. 

Yes, we know, not quite the straightforward answer you're looking for. Still, we’re here to help. The slight complication arises due to US recycling programs often operating on one of two methods: single-stream recycling or multi-stream recycling.

“In most recycling systems, it is better not to crush your cans,” Matt Meenan, senior director of public affairs at the Aluminum Association, told IFLScience. “The reason is that in 'single-stream' recycling (where all materials are intermingled in a single bin), the cans must be separated from the rest of the materials by an electrical current called an ‘eddy current.’”

Due to their smaller surface area when crushed, it’s more difficult for this eddy current to properly sort the cans. “So, in these cases, the cans may get lost or sorted incorrectly into bales of plastic, glass, paper or other recyclables.”

However, “In multiple-stream recycling,” the US Environmental Protection Agency (EPA) added, “where recyclables are separated during collection, crushed cans can help save space, making it more efficient to transport them to the materials recovery facility. In this scenario, the cans can be either be crushed or un-crushed.”

One may ask, if multi-stream recycling is better equipped to handle aluminum, why don’t we use that method at all times? While that’s true, past studies have shown that single-stream recycling also tends to promote greater recycling in general and reduces recycling collection costs. However, single-stream recycling may not actually have a significant impact on reducing the amount of waste that ends up in landfills, according to a 2006 study. The mathematics on the cost-benefit ratio is complicated, in part due to the rates of contamination from everything from dirty diapers, to broken syringe needles, to batteries and Christmas lights in recycling bins. In fact, some estimates suggest that around 25 percent of what we attempt to recycle is too contaminated and ends up in the landfill anyway. 

More than 60 percent of recycling programs in the US are single stream, up from 29 percent in 2005. Aluminum specifically accounted for an estimated 1.8 million tons of packaging in 2015, according to the EPA. Of that total, 670,000 tons of aluminum beverage cans were recycled, 240,000 were combusted, and a whopping 940,000 tons were landfilled. 

So what can you do to ensure your can gets recycled properly? 

US Environmental Protection Agency

“We suggest people contact their local recycling department for advice on whether or not to crush aluminum cans.”

Susan Robinson, federal public affairs director of Waste Management

“It’s important that the cans are empty, as a cans with liquids can’t be projected into the correct bin (we use an eddy current and an air jet to shoot the can into an aluminum bin).”

“We do not want Aluminum aerosol cans due to mills refusing to accept them as they are an explosion hazard in their processing.”

Matt Meenan, senior director of public affairs at the Aluminum Association

“I’d say the most important takeaway is to recycle your cans,” added Meenan. “It takes 90+ percent more energy to make brand new aluminum versus recycled aluminum. The other nice thing about aluminum cans is you can recycle them over and over again in a closed loop system. But, every can you throw away is a can that doesn’t go back into that cycle.