In the pursuit of adopting more sustainable habits, recycling is low-hanging fruit. It takes minimal effort to pop your recyclables—empty glass bottles, old paperwork, and the like—into their designated bins, which have become commonplace next to trash cans in both homes and many public spaces. But as recycling has become almost second nature to many, it’s also become easier to do incorrectly. This tendency, aptly termed “wishcycling,” refers to tossing something into a recycling bin with the hope or wish that it’ll be recycled, even though it very well might not be recyclable at all.

“Speaking as a former wishcycler, I used to think that it was better to give an item the ‘opportunity’ to be recycled rather than just putting it directly into a trash can for it to end up in a landfill,” says Katie Tyson Higdon, co-founder and Chief Commercial Officer of sustainable online marketplace Hive. And she’s not alone: The average recycling contamination rate in the U.S. is 25 percent, which means that one in four items placed into a recycling bin is actually not recyclable (at least by way of a municipal curbside recycling system)—and either ended up there by pure mistake or misdirected wishcycling.

No matter the reason, though, wrongly recycled items can backfire big-time. “Even if well-intended, aspirational recycling costs financially strapped recycling facilities more money to process the waste that they can’t recycle, which can also damage machinery,” says Higdon.

“Aspirational recycling costs financially strapped recycling facilities more money to process the waste that they can’t recycle.” —Katie Tyson Higdon, co-founder and COO of Hive

To prevent that time-consuming and costly scenario, many municipalities will simply send an entire bin’s contents to a landfill (not just the wishcycled item) if they suspect it contains something un-recyclable. “The old adage of ‘a bad apple spoils the whole bunch’ actually does apply to curbside recycling,” says sustainability expert Ashlee Piper, author of Give a Sh*t. Do Good. Live Better. Save the Planet. The result: Even recyclable items can end up piling onto landfill trash because they were in the same bin as a wishcycled (aka un-recyclable) item.

Of course, that’s just the opposite effect from what most wishcyclers intend to happen. So, why is wishcycling so rampant? In short, recycling appropriately in this country isn’t nearly as straightforward as it might seem, largely because each municipality can create its own set of rules, which aren’t necessarily the same as the next, says Piper.

That said, there are still a few universal pointers to keep in mind. Below, experts share the most commonly wishcycled items (so you can avoid making the same ill-fated choice), along with a few eco-conscious ideas for how to dispose of, reuse, or recycle these things more effectively.

The 6 most common culprits of wishcycling (all of which *cannot* be recycled in your curbside bin)

1. Multi-material items

If an item is made of more than one material—typically plastic and something else, like paper or metal—there’s a good chance it can’t be recycled curbside, unless the components can be taken apart and separated, according to Piper. Most books and packaging for cosmetics and household items fall into this category, as do pasta boxes with clear plastic windows (more on plastics below). In that particular case, you can remove and discard the plastic window in the trash and then drop the cardboard box into your recycling, says Higdon.

2. Broken glass, metal, or mirrors

Not only can these pieces damage recycling sorting machines (or if they’re very small, miss the sorters entirely), but more importantly, they can injure the people who sort through recycling in many cities, says Piper. As a result, these should just be thrown out.

3. E-waste

Also known as Waste Electrical and Electronic Equipment (WEE), e-waste is any form of electronic waste with a plug or battery, says Lea D’Auriol, founder of environmental nonprofit Oceanic Global. “To be safely and effectively recycled, e-waste needs to be collected by a specialized recycler separate from your curbside or municipal recycling program,” she says. In other words? No, you can’t just drop old cell phones, chargers, cables, or speakers into the recycling bin.

While universities and electronics stores often have e-waste recycling programs and community drop-off options, you can also participate in Google’s recycling program by requesting a free postage-paid shipping label and then sending any devices (Google or otherwise) to be recycled responsibly. (Another option? If your old device isn’t totally destroyed, you can use a platform like BackMarket to sell it to expert refurbishers.) Separately, retailers like Staples and Best Buy safely recycle dead batteries from devices, which can otherwise leach toxic metals into the environment, adds D’Auriol.

4. All sorts of un-recyclable plastic

As a disclaimer, this category is where the experts are most forgiving of wishcyclers, given the fact that plastics are very difficult to recycle correctly, if at all. (And that’s why your best bet here is always going to be reducing your usage of plastic from the get-go.)

“The misleading recycling symbol on many plastics is one of the reasons why less than 10 percent of the 7 billion tonnes of plastic waste generated globally so far has been recycled,” says Laura Wittig, co-founder and CEO of eco-conscious platform Brightly. “Unfortunately, just because something has a recycling symbol on it doesn’t mean it’s actually recyclable in your curbside program.”

That’s where the number inside the recycling symbol comes into play, at least as a starting point. If you remember just one thing about plastics, know that numbers 1, 2, and 5 tend to be the only ones that are recyclable. “That means jugs, bottles, and large plastic containers, like a clamshell for spinach, can usually be recycled,” says Piper.

Outside of that, keep in mind that number 3 (polyvinyl chloride, typically found in shower curtains), number 4 (low-density polyethylene, found in flexible plastics like plastics bags and wrappers), number 6 (polystyrene, aka styrofoam found in takeout containers, coffee cups, and foam packaging), and number 7 (which is a blend of plastics that didn’t fit into the above six categories) cannot generally be recycled curbside, says Wittig.

A couple other no-gos that you’d be wise to avoid wishcycling? Plastic hangers, plastic cutlery, and black plastic, “which is commonly used in takeout and microwave meal containers and cannot be effectively detected by recycling sorting machines,” says D’Auriol.

Because there are so many types of plastic out there, and some items might not be properly labeled with their recycling number, if you’re ever in doubt, it’s best to check with your municipal recycling company directly, or search the item in Earth911’s database to determine your best mode of action, says Higdon.

5. Anything with food or liquid residue on it

Even if the material itself is curbside recyclable (like, say, a glass jar or one of the recyclable plastic containers noted above), if there’s any sort of food or liquid residue on it, it’ll contaminate your recycling. Instead of wishcycling the dirty item, take the time to rinse it out and dry it before popping it into the appropriate recycling bin, says Piper.

That also means greasy cardboard pizza boxes should not be recycled, given it’s not possible to remove the residue completely, according to Higdon, who suggests placing these in a community compost bin (if there’s one in your neighborhood), where they’ll break down over time.

6. Very small things

“Anything the size of a Post-it Note or smaller will usually miss the sorter and cannot be recycled,” says Piper, who adds that small paper bits can be composted. That also means you should be careful not to toss loose plastic bottle caps into your bin, either, says Wittig: “These can jam the machinery at the recycling center, which is why some centers recommend that you remove them, wash out the bottle, and then put them back on before recycling.”

What to do with items that can’t be curbside recycled

Recycle them through a specialized program

Multi-material items, certain types of plastic, and too-small-to-recycle pieces can often be recycled through specialized programs, where they can be taken apart or otherwise processed by hand. “We’ve found that some cities, like Austin, have more robust recycling centers where you can drop off less commonly recyclable items,” says Higdon. “And there are some emerging companies, like Ridwell, which are attempting to create new recycling streams for hard-to-recycle items.”

The experts also suggest utilizing TerraCycle, which offers free zero-waste boxes for a variety of tough-to-recycle items; pick one that makes sense for your waste, and it’ll come with a prepaid shipping label, so you can just send it back once it’s full, and they’ll handle recycling the items into raw manufacturing materials for things like park benches and roof tiles.

Repurpose or reuse them

Your creativity is the only limit here: “There are DIYs for oh-so-many things that get wishcycled,” says Piper. “Make mosaics out of broken glass and tile. Reuse takeout cutlery and containers to make a container garden and sprout seeds. Check with your local ‘Buy Nothing’ group to see if crafters want any of your non-recyclables.”

And, of course, glasses and jars of all sorts can easily be the stuff of kitchen-organization dreams, she adds. Just clean them out, paint the lids in a uniform color, and they’re as good as—or even better than?—new.

Donate them

Items like books and household decor can almost always find a second life with someone else. Rather than subject these multi-material pieces to a landfill by way of wishcycling, donate them to your local Goodwill, library, school, or other nonprofit organization (right along with your used clothing). The same goes for durable medical equipment, like crutches and wheelchairs, and mattresses, says D’Auriol, all of which is almost always better off used again than thrown out or mistakenly recycled.

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