About half of everything Americans throw away ends up in a landfill, and only about a third gets recycled or composted. In 2018, the U.S. generated 292.4 million tons of municipal solid waste. Of that, roughly 69 million tons were recycled and 25 million tons were composted, for a combined diversion rate of 32.1 percent. The rest was either landfilled (50 percent) or burned for energy (11.8 percent). But those numbers mask huge differences between materials. Some things you toss in the blue bin are recycling success stories. Others barely get recycled at all.
Cardboard and Paper: The Clear Winners
Corrugated cardboard is the single most successfully recycled material in the waste stream, with a recycling rate of 96.5 percent. Nearly every box that gets broken down and put in recycling actually becomes new cardboard. The demand from manufacturers is strong, the collection infrastructure is mature, and the material is easy to process.
Other paper products don’t do nearly as well. Paper containers and packaging that aren’t corrugated boxes had a recycling rate of just 20.8 percent in 2018. The gap comes down to contamination. Greasy pizza boxes, paper cups with plastic linings, and shredded paper that’s too small for sorting machines all end up as waste. Clean office paper and newspapers still recycle well, but the mixed paper category drags the overall number down.
Paper fibers do degrade with each recycling pass. Every time paper is pulped and reformed, the cellulose fibers get shorter and weaker. Most paper can go through five to seven cycles before the fibers are too short to hold together, at which point they’re typically composted or used as filler material.
Aluminum: Infinitely Recyclable, Often Wasted
Aluminum is the ideal recycling material. Unlike paper or plastic, it can be melted down and reformed with no loss in quality, no theoretical limit on how many times it cycles through. A small amount of metal is lost to oxidation during processing, but the remaining aluminum is fundamentally unchanged. A recycled can becomes a new can that’s identical to one made from raw ore.
Recycling aluminum also uses roughly 95 percent less energy than producing it from scratch, which makes it one of the most economically worthwhile materials to recover. Despite this, Americans still landfill billions of cans each year. The recycling rate for aluminum cans hovers around 45 to 50 percent, largely because cans get tossed in regular trash at restaurants, stadiums, and public spaces where recycling bins aren’t available or aren’t used.
Glass: Easy to Recycle, Hard to Collect
Glass, like aluminum, can be recycled indefinitely without degrading. Crushed glass (called cullet) melts at a lower temperature than raw materials, saving energy at the manufacturing stage. Glass processors accept virtually any glass that arrives at their facility, adjusting payment based on contamination levels rather than rejecting loads outright.
The problem with glass is logistics. It’s heavy and breaks during collection, contaminating other recyclables in the same bin. Many curbside programs have dropped glass entirely because the cost of hauling it outweighs the revenue from selling it. In single-stream systems where everything goes in one bin, broken glass embeds in paper bales and damages sorting equipment. Communities that still collect glass often get the best results with dedicated drop-off bins rather than curbside pickup.
Plastic: Most of It Doesn’t Get Recycled
The overall plastic recycling rate in the U.S. was 8.7 percent in 2018. Out of the massive volume of plastic waste generated, only about three million tons were actually recycled. The recycling symbol stamped on a plastic container tells you what type of resin it’s made from, not whether anyone will actually recycle it.
Two types of plastic get recycled at meaningful rates. PET (the clear plastic used for water bottles and food jars, marked with a #1) had a recycling rate of 29.1 percent. HDPE (the sturdier, often opaque plastic in milk jugs and detergent bottles, marked with a #2) came in at 29.3 percent. These two polymers have established markets because manufacturers can use the recycled material to make new bottles, polyester fiber for clothing, or plastic lumber.
Everything else, plastics #3 through #7, is recycled at negligible rates. Yogurt cups, clamshell containers, plastic bags, styrofoam, and most food packaging either have no market or cost more to process than the recycled material is worth. Many recycling programs accept these items at the curb to keep things simple for residents, but much of it gets sorted out at the processing facility and sent to landfill anyway.
Plastic also degrades with each recycling pass. Traditional mechanical recycling breaks down the long polymer chains, producing lower-quality material each time. A water bottle might become fleece fabric or decking material, but those products typically can’t be recycled again. This “downcycling” means most plastic gets one second life at best before it reaches the landfill.
What Happens at the Sorting Facility
After your recycling is collected, it goes to a materials recovery facility (MRF, pronounced “murf”), where machines and workers sort it by material type. Optical sensors identify different plastics by their chemical signature. Magnets pull out steel cans. Eddy current separators repel aluminum. Screens separate flat paper from round containers. The sorted materials are compressed into bales and sold to manufacturers.
Contamination is the main threat at this stage, but it doesn’t work quite how most people think. Facilities rarely reject entire loads outright. Instead, contamination drives down the price. A plastics processor may pay full price for bales with less than 10 percent contamination but downgrade dirtier loads by as much as $100 per ton. Glass processors similarly accept most loads but adjust payment based on quality. The system is more of a sliding scale than a pass/fail test.
That said, contamination does cause real losses. Food residue on paper makes it unrecyclable. Plastic bags jam sorting machinery and shut down processing lines. Non-recyclable items mixed in with recyclables force workers to pull them by hand or let them contaminate a bale. When contamination gets bad enough, the entire bale becomes worthless and goes to landfill. China, which once purchased enormous quantities of American recyclables, began requiring inspections of every inbound load and rejecting fiber bales with more than 10 percent waste. That policy shift in 2018 upended the U.S. recycling market and left many communities scrambling to find buyers.
What You Put in the Bin That Shouldn’t Be There
The items that cause the most problems at sorting facilities are things people assume are recyclable but aren’t, at least not through curbside programs. Plastic bags and film wrap top the list. They tangle in sorting equipment and require facilities to shut down for manual removal. Even if they’re technically recyclable, they need to go to separate drop-off bins at grocery stores, not in your curbside bin.
Other common contaminants include food-soiled paper (greasy pizza boxes, used napkins), small items that fall through screens (bottle caps, shredded paper), and “tanglers” like garden hoses, wire hangers, and string lights that wrap around machinery. Electronics, batteries, and medical waste are hazardous contaminants that can injure workers and should never go in recycling.
The simplest rule: if you’re not sure whether something is recyclable in your specific community, it’s better to throw it in the trash. Tossing something questionable in the recycling bin, sometimes called “wish-cycling,” creates more problems than it solves. It contaminates otherwise clean loads and drives up processing costs for materials that would have been recycled successfully.
Why Some Recyclable Materials Don’t Get Recycled
Recycling is ultimately a market. Materials get recycled when someone is willing to buy them at a price that covers the cost of collecting and sorting them. Aluminum and cardboard have strong, stable markets, so they consistently get recycled. Mixed plastics and glass often don’t, because the raw materials they replace are cheap and the processing costs are high.
Geography matters too. A community near a paper mill or aluminum smelter can sell recyclables cheaply because transportation costs are low. A rural community hundreds of miles from the nearest buyer may find that landfilling is simply cheaper than recycling for certain materials. This is why recycling programs vary so much from city to city. What gets recycled in Portland may go to landfill in a smaller town two hours away.
Chemical recycling, which breaks plastics down to their molecular building blocks rather than just grinding and remelting them, has been proposed as a solution for hard-to-recycle plastics. These processes can recover high-quality raw materials, but they require significant energy and chemical inputs, making them much more expensive than mechanical recycling. For now, they remain a small-scale supplement rather than a replacement for traditional methods.