For many, recycling at home is second nature. The junk mail, the cardboard, the soup cans, the yogurt tubs, the peanut butter jars – we keep such items out of the garbage can and instead place them in recycling bins.

But the recycling ritual also comes with questions. Why the tubs but not the lids? How clean does the peanut butter jar need to be? Why can’t I recycle more plastics at home?

The answers to questions like these lie in the fact that once it leaves your bin, that jumble of paper, metal and plastic, along with the separated glass, all has to be sorted and then sold. Those empty containers and torn newspapers are commodities – goods sold to buyers in the region and around the world. They’ll be used to make new products.

From your bin to a sorting center

At Far West Recycling in Hillsboro, trucks dump out loads of recycling they’ve collected. The mishmash is then shoveled onto a series of conveyor belts to be sorted. Screens separate lightweight paper from heavier cardboard and flat paper from bulkier cans and tubs. This is where those plastic lids cause problems. They’re flat and can be mistakenly sorted as paper, making the paper harder to sell.

Farther along the line, magnets pull steel cans from the belts and another machine separates aluminum cans. Workers pull extension cords, plastic bags and metal wire from the line. These can wrap around the machinery and bring the conveyors to a halt.

Operations manager Vinod Singh has worked at several Far West facilities since 1990. When he started, there were no mechanized sort lines. “We used to sort everything on the floor,” he says.

At that time, newsprint was a profitable commodity that made up 75 percent of recyclables collected from residents. But, he says, with the decline of newspapers and the rise of the Internet, “we don’t get a lot of newsprint. It’s maybe 15 percent now.”

From sorting center to market – at home and abroad

What Singh is really talking about is the economics of recycling. In fact, a key consideration in what is and isn’t accepted in home recycling bins is whether any given material, such as paper, can be sold. “Material” because that’s what it is on the market, material to make stuff with. And the recycling system we use at home is set up for materials for which there is a consistent and dependable market demand.

That newsprint Singh talks about goes to local mills. And while there is much less of it these days, Singh says there’s now “decent demand from local mills for cardboard” because of the meteoric rise in online shopping. The mills mix recycled paper with virgin fiber to make new paper and cardboard.

“Well over half the paper [that’s recycled] stays in the region,” says Jerry Powell, executive editor at Resource Recycling, which publishes recycling trade magazines and sponsors industry trade shows.

The rest of the paper, including most of the junk mail goes mainly to China, along with many plastics and some scrap metal.

In fact, international demand for recycled materials from the U.S. is huge. “Recycling is the biggest export on a tonnage basis from the West Coast,” says Peter Spendelow, solid waste policy analyst at the Oregon Department of Environmental Quality.

Glass, though, stays local. “In Oregon we have a nice, controlled clean stream of high-quality glass,” says Spendelow.

That’s in part because of the Oregon bottle bill, and in part because in the Portland region, we keep the glass we recycle at home “on the side.” When glass is mixed with other recyclables, it’s crushed and then used mainly as landfill liner or roadbed. But here, glass goes to a cleaning facility and then on to a plant near the Portland airport where it's used to make new bottles.

So, about that peanut butter jar, while remnants of food are destroyed when the glass is melted, they still need to be pretty clean to avoid attracting pests as they sit in your bin, at the recycling center or at the glass plant.

Beyond economics: The value of recycling is about the value of resources

Making glass from recycled bottles uses about 30 percent less energy than making new glass from lime and sandstone. And like aluminum and steel, it’s infinitely recyclable. “We want to capture the value of these resources,” says Andy Sloop, resource conservation and recycling manager at Metro. It’s part of Metro’s job to ensure that the Portland region recycles as much as possible.

Sloop says the benefits of recycling are greater when you account for the whole life of the items you recycle, including the impact of producing those items.

Take the aluminum in that empty soda can. It began as bauxite deep in the earth in places like Jamaica, Malaysia or Suriname. It’s extracted by strip-mining which removes plants, and along with them, habitat and food for wildlife. Mining also produces heavy metals that pollute water and air. And the process of transforming bauxite into aluminum requires a lot of energy and releases climate pollution. Recycling that soda can extends the life of the bauxite used to make new products and reduces the need to extract more.

So, the cans sorted in Hillsboro go to smelters in the United States and abroad. These scrap smelters consume 95 percent less energy and produce 95 percent fewer emissions than smelters that make aluminum from bauxite.

“You can transport aluminum hundreds of thousands of miles by train before you get anywhere close to using the energy needed to produce it from virgin materials,” says DEQ’s Spendelow.

Similar types of plastic are baled together for sale in recycling markets.

Markets for plastics are more complicated

Huge bales of crushed milk cartons, water bottles and mixed plastics are stacked outside the sorting hall at Far West Recycling. Some stay onshore and some go to China.

Demand for plastics has lessened since China’s economy slowed down, says Singh. Plastics markets are directly tied to oil prices and oil is so cheap right now that it’s often less expensive to make new plastic than to pay to sort and clean recycled plastic. “We’re hoping we’ve hit that bottom curve,” says Singh.

But even when markets for recycled plastics are stronger they’re still complicated. Many items – like the clamshells that hold our salad greens or take-out dinners – aren’t recyclable in the home bin. That’s partly because sorting facilities set up before these containers became so common may not be equipped to process them efficiently. And also because the markets for clamshells and other types of plastics have not become dependable. The plastic that makes those salsa tubs and shampoo bottles is easier to sell so that’s why they’re a part of the regional collection system.

And like those glass jars, plastic should be clean, too. Dirty plastic doesn't fare well in the recycling process, and it may not be as marketable either.

Plastic bottles collected at redemption centers go to the new ORPET recycling plant built near St. Helens after the bottle bill was expanded in 2009. “That’s a real success story,” says Powell.

And it’s a success that goes beyond the bottom line, beyond low oil prices or dips in demand. As Powell sees it, recycling is an essential part of a vibrant regional and worldwide economy. “If all curbside recycling ended tomorrow, our highways could not be rebuilt, our newspapers could not be published, our beverages could not be bottled and canned.”