With the vast majority of U.S. towns and cities opting to let residents toss all their recyclables in one blue bin (and leave the sorting to machines), here are five ways residents can make sure more of what they bother to recycle actually gets reused:

[Read more: American recycling is stalling, and the blue bin is one reason why]

1. Do not bag your recyclables.

Yes, it’s less messy to put all those leaky bottles and cans in a bag and take them to the curb later. But the first thing recyclers have to do is to break open every paper or plastic bag. And with conveyor belts moving at speeds of 35 to 60 feet per second, sorters don’t have time to open every well-tied bag and make sure what’s inside won’t damage machinery later on. More often than you’d probably like to know, a full bag of recyclables can get diverted to the trash pile.

The sorting line at Waste Management’s Elkridge, Md., recycling facility. Aaron C. Davis/The Washington Post
2. Just because it should be recyclable, doesn’t mean it is.

Yes, a garden hose is rubber. So is the sole of a shoe. A Halloween costume is plastic, and so are Christmas lights. A few viral Internet stories about China reusing such items don’t mean that your local recycling facility is equipped to handle them. Long, stringy things are some of the worst for recycling machinery and can shut down an entire line. Another surprise: In most cities — including the District — pizza boxes are NOT recyclable.

A Halloween costume is removed from machinery after it was caught in a sorter. Aaron C. Davis/The Washington Post.
3. Concrete, barbells, hypodermic needles!

Seriously, see above. Not recyclable. At the Materials Recovery Facility in Elkridge, Md., which handles all blue-bin contents from the District and Baltimore, sorters wear rubber guards up to their elbows to protect against things that should really never be sent through the normal recycling stream. That includes a scary amount of hypodermic needles. Apparently it’s a thing to put used needles in a plastic water bottle and then put that bottle of biohazard in the blue bin. Every week, the Maryland facility ships to a medical waste company a 35-pound box filled with used needles.

A box of hypodermic needles at the Elkridge, Md., sorting facility. Aaron C. Davis/The Washington Post.
A box of hypodermic needles at the Elkridge, Md., sorting facility. Aaron C. Davis/The Washington Post.
4. Don’t worry about every last drop of whatever.

Yes, recyclables should be clean, but they do not have to be sterile. Trust me. The odor at a recycling plant is only a shade better than your average garbage dump. In fact, a few drops of water in a super-lightweight plastic bottle can help ensure that it gets pushed in the right direction, (and not blown up in the air with paper waste). The crushers and balers will squish out the last drops. That said, don’t be lazy and leave the Styrofoam, plastic and peanut packaging in with the cardboard – there’s a good chance it will mean the whole box gets directed back to the landfill.

5. When you can, sort.

Some large cities, including Nashville and Salt Lake City, have never allowed glass in their recycling bins and have separate drop off locations for that material. Anywhere sorting is offered, use it. Perhaps the single most important thing you can do is NOT put plastic shopping or newspaper bags in the recycling bin. Take those back to the grocery store. In the Maryland facility, recyclers have to shut down each line every two hours to scrape hundreds of plastic bags out of the system.

Bonus points: Composting.

Environmentalists say the next frontier in U.S. recycling is to go the way of San Francisco, Seattle and Portland and institute citywide composting. By mandating that residents separate food scraps and grass clippings, San Francisco now claims to be recycling about 80 percent of all waste. If done on a large scale, composting might have a more direct impact on global warming, environmentalists say, than keeping any plastic bottle or can out of the garbage. By some estimates, organic material rotting in landfills is now the country’s third biggest source of methane gas.