We’re taught to reduce, reuse and most of all, recycle. For most of us, that means tossing a water bottle into the blue bin and moving on with our days. But have you ever wondered what happens next?

To find out, I followed milk jugs, soda cans and office paper on their smelly journey from bin to bale. Clad in a neon yellow vest, safety glasses and hard hat, I climbed through the intricate mazes of Seattle’s two main recycling plants, run by Republic and Recology CleanScapes.

As my eyes and ears were assaulted by industrial machinery, I learned some pretty surprising things about recycling — a multibillion dollar industry.

1. It’s an industry, not just a public service

The government doesn’t deal with our trash; private companies do. The city of Seattle contracts with Republic, Recology CleanScapes and Waste Management for residential waste disposal, and the three companies have individual contracts with commercial businesses. When it comes to recycling, these companies sell the contents of your blue bin as commodities in the domestic and world market.

The main purpose of a recycling plant (known in the business as a “materials recovery facility,” or MRF) is to precisely sort each type of recyclable into massive bunkers, where the piles of materials are then baled and shipped across the country, where other companies in turn deal with the actual recycling — the melting down of aluminum, plastic and glass and the pulping of paper and cardboard.

2. The sorting is amazingly high-tech

Top dollar is paid for the least contaminated materials, so Seattle-area MRFs use all sorts of innovative technologies in the sorting process. For instance:

• An optical sorter uses infrared light technology to detect the type of polymer in plastics. At Republic, a series of two optical sorters are used. The first targets puffs of air at containers, blowing them out of the mixed paper stream. The second identifies the type of plastic, efficiently directing PET plastics (water and soda bottles) into one bin, HDPE natural plastics (milk jugs) into another bin, and the rest of the mixed plastics into a third bin for baling.

• A powerful magnet captures steel cans as they pass underneath it on a conveyor belt.

• An eddy current, which works similarly to a reverse magnet, uses a magnetic field that polarizes aluminum cans and pops them over a partition into a bunker.

• A Nihot glass separator (Recology operates one of only two in the nation) separates glass based on density and prevents contaminants like dirt from diluting the quality of the product.

3. The human factor remains vital to the operation

Despite the impressive machinery involved in sorting recycling into commodities, quality control is still done by hand. At Republic’s MRF, two shifts every day are staffed by 36 sorters stationed at different points along the processing line, with three forklift operators and three loader operators. At Recology, the sorting speed standard for workers is 40 picks a minute, which amounts to workers frantically pulling out contaminants and recycling that slipped through the screening system. Imagine doing that for eight hours a day.

4. Aluminum cans are recyclers’ favorite commodity

Aluminum cans are 100 percent recyclable and can be recycled an infinite number of times (as opposed to paper, which has less and less fiber the more it is recycled). Republic moves about one load of aluminum cans every week — a load is 40 bales, each of which weighs 1,000 pounds and contains 30,000 cans. That’s 1.2 million cans a week. The cans travel by rail to the southeast, where most of the nation’s aluminum recyclers are clustered. There, the cans are melted down, flattened into sheets and cut into new cans. The empty cans are then shipped to beverage companies and distributed to stores across the country. It takes about one to two months for an aluminum can to end up back on the shelf after it’s tossed in the recycling bin.

5. What to (not) recycle

All sorts of strange things end up in recycling.

Todd Burnstein, an account manager at Recology Cleanscape’s MRF in Sodo, had to deal with a proliferation of deer hides at a plant in Missoula, Mont. Thankfully, people in Seattle know that animal skins aren’t recyclable, but they did get a firework in the aftermath of July Fourth.

Just because something is technically recyclable doesn’t mean you should put it in the blue bin. Sorters regularly pull out jeans and tire chains because they get caught in the machinery’s rotating disks. A sticky peanut butter jar is recyclable, but the amount of water needed to clean it out is a costly natural resource that negates the value of recycling it.

Other things that aren’t recyclable: bottle caps, prescription vials, mirrors, window glass, aluminum foil, zip-lock bags.

6. The numbers look pretty good

Seattle recycles nearly 60 percent of all municipal solid waste, and the number has been growing every year. The recycling rate — the percentage of waste that is kept out of the landfill by reuse, recycling or compost — is up 18 percent since 2003. In 2013, Seattle had 9,288 more tons of recycling than in 2012.

The residual rate — the non-recyclable waste that ends up in the blue bin — is only about five percent.

The county estimates that the average King County resident generates more than 16 pounds of garbage per week or about half a ton of garbage per year.

7. When in doubt, don’t throw it out — get educated

The catch phrase “When in doubt, throw it out” doesn’t apply as much as it used to, especially considering that recycling is sorted for contaminants and waste going to the landfill isn’t.

According to the 2013 King County Comprehensive Solid Waste Management Plan, 63 percent of materials disposed at the Cedar Hills landfill in 2011 were easily recyclable (including food scraps and food-soiled paper, paper, yard waste, clean wood, aluminum, tin cans, plastic and glass) and another 15 percent of materials had limited recycling options (such as plastic wrap and bags, carpet, polystyrene foam and asphalt). Ouch. That means that more than three-quarters of the waste in King County’s main landfill is recyclable in some capacity.

Part of fixing this problem comes down to education. Make sure to check the signs under the lids of residential bins to remind yourself what goes where. Even commercial facilities are starting to use signs above their recycling, compost and waste bins to jog their patrons’ memories.

“There’s definitely a long term attempt to educate and go further, what other signage can we do, what other incentives can we provide to help kids understand why they’re doing this,” said Anne Laughlin, area director of public relations and field communications at Republic. “As we see generations grow, recycling is going to get that much better.”