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Food-Contaminated Paper and Cardboard
Think pizza nights are fun? Well, your greasy pizza box might be killing the recycling party. Food-contaminated containers with more than eight percent of food or drink residue cannot be recycled, particularly items like greasy pizza boxes and unrinsed bottles. The oil from pizza seeps into the cardboard and cannot be separated from the fiber during the pulping process. This contamination makes the entire batch of recyclables less valuable and harder to process.
Even that innocent-looking napkin from your lunch becomes a recycling nightmare once it touches food. Paper products contaminated with food, grease, or other substances are non-recyclable, including used paper towels, napkins, and tissues, because contamination prevents the paper fibers from being properly processed. Food and liquids in recycling cause mold, and a cardboard pizza box covered in grease has the same characteristics as a clean box, but the system cannot differentiate and it can degrade an entire recycling load.
Styrofoam and Expanded Polystyrene
That white foam container from your takeout dinner isn’t going anywhere – literally. Very few localities accept styrofoam in curbside recycling, and there’s a scientific reason behind this frustrating reality. EPS is comprised of more than ninety percent air, making it lightweight and bulky, meaning the collection and transportation impacts often outweigh the environmental benefits.
Most people see the recycling symbol with number six and think it’s recyclable, but that’s where the confusion starts. Although foam containers have the chasing arrows symbol, those foam egg cartons, meat trays, peanuts, or any other type of EPS are not recyclable in curbside recycling. In most curbside recycling programs, EPS is part of recycling contaminants that cannot be recycled curbside and can cause entire loads of recycling to be rejected. The irony? While expanded polystyrene can be recycled, it is expensive and not accepted in most curbside recycling programs.
Broken Glass and Certain Glass Items
Your favorite coffee mug just shattered, and you’re thinking about tossing it in the recycling bin – don’t. Broken glass is not recyclable, and glass that is broken or sharp cannot be recycled. Broken glass can be very dangerous for recyclers and service providers, should never be recycled with other materials, and should be wrapped in newspaper and thrown in the trash.
The glass situation gets even trickier when you consider that not all glass is created equal for recycling purposes. You cannot recycle drinking glasses, eyeglasses, glass furniture, mirrors, or light bulbs. Drinking glasses, canning jars, Pyrex, window glass and ceramics are not accepted. Ceramic items such as plates, mugs, and cookware, along with certain types of glass like window panes, mirrors, and light bulbs, cannot be recycled with standard glass recycling.
Batteries of All Types
Here’s something that might shock you – literally and figuratively. Most batteries, including lithium-ion, lithium metal, lead-acid, nickel cadmium, and other rechargeable batteries, should not go in household garbage or recycling bins. No batteries of any kind are accepted in curbside recycling, ever, because lithium batteries can cause fires.
The reason behind this strict rule isn’t just about fire safety – it’s about proper resource recovery. These batteries require special handling and should be taken to specialty drop-off locations or household hazardous waste collection points. Vape batteries produced in 2022 contained 286,000 pounds of lithium, but although lithium recycling is technically feasible, it’s not economically viable, with only 13,000 pounds recovered from all e-waste – less than five percent of what was needed for disposable vapes alone. This means valuable materials are literally going to waste because our recycling systems can’t handle them properly.
Electronic Waste and Small Appliances
Your old phone might seem small and harmless, but it’s packing some serious environmental punch. The world’s generation of electronic waste is rising five times faster than documented e-waste recycling, with 62 million tonnes produced in 2022. About eighty-two percent of electronic waste is not recycled through official channels and cannot be accurately tracked.
The challenge with electronics goes beyond just volume – it’s about what’s inside them. Electronics and batteries contain hazardous materials and should never be placed in curbside recycling bins because improper disposal can lead to toxic leaks and environmental contamination. Small appliances like microwaves, vacuums, IoT devices and vapes compose the largest portion of global electronic waste at 45 billion pounds annually, yet less than one-eighth is collected for recycling.
Textiles and Clothing
That old t-shirt you’re ready to toss might seem like it belongs in recycling, but your curbside bin isn’t the right place for it. Textiles are recyclable, but placing them in the recycling bin with other recyclables will contaminate the designated recycling stream. Textiles are among the contaminants that must be removed from recycling each week because they could become wrapped around sorting facility equipment, causing extensive damage.
The textile recycling challenge is compounded by contamination risks at sorting facilities. Due to mixed recycling collections, textiles could be contaminated by unidentifiable liquids and broken glass, which is impossible to remove. Instead of tossing clothes in regular recycling, it’s recommended to sell them, donate them, or drop them off at charity shops, clothing banks, or recycling sites, with many councils providing separate clothing collections.
Certain Plastic Types and Complex Packaging
Not all plastics are created equal, and those little numbers on the bottom don’t guarantee recyclability. While many plastics are recyclable, plastics labeled with numbers 3 (PVC), 6 (polystyrene), and 7 (other) are often non-recyclable in standard curbside programs because they are more complex and expensive to process.
The problem gets worse when you consider multi-material packaging. Packaging such as chip bags, juice pouches, and candy wrappers are often made from mixed materials that are difficult to separate and recycle. High-quality waste sorting for recycling is challenging as packaging materials tend to be produced with various material combinations and often get discarded into assorted trash, with only certain plastic materials undergoing recycling. Packaging materials contaminated with food or other materials make it difficult to clean and decontaminate for subsequent use, with recyclability mainly based on decontamination efficiency.
Plastic Bags and Flexible Films
Here’s a recycling fact that might bag your mind: Plastic bags are the number one contaminant found in recycling containers nationwide, though many grocery stores and big-box retailers take back plastic bags for recycling. The reason they’re such a problem is mechanical – plastic bags can damage equipment at processing facilities when they get wrapped around moving parts, will not be opened at facilities, and will be sent to landfill.
Even the recycling industry has a specific term for items like plastic bags: “tanglers.” Plastic bags, wires, clothing and string lights get tangled in mechanized sorting equipment at recycling facilities, damage the equipment, stop the process until someone can de-tangle them, and cannot be recycled at regular facilities. While technically made from recyclable plastic, thin plastic bags clog up recycling equipment, causing major delays and potential harm to workers.
Aerosol Cans and Hazardous Materials
That empty spray paint can might look harmless, but it’s hiding some dangerous secrets. Aerosol cans that are not completely empty pose a risk because they can explode under pressure, and even empty cans are commonly not accepted due to potential presence of hazardous materials. The recommendation is to use non-aerosol alternatives when possible, dispose of aerosol cans at hazardous waste collection sites, and ensure cans are completely empty before disposal.
The broader category of hazardous household materials creates similar challenges. Items such as paint, pesticides, cleaning chemicals, and automotive fluids are classified as household hazardous waste requiring special handling because they can be toxic and pose risks to both human health and the environment. No flammables, motor oil, paint or batteries are accepted, including plastic motor oil bottles.
Ceramic and Heat-Resistant Cookware
Your grandmother’s ceramic casserole dish might have sentimental value, but it has zero recycling value. Most recycling facilities are not able to melt down ceramics for recycling, though local drop-off sites may accept and recycle ceramics. The fundamental issue is that ceramics are made through high-temperature firing processes that change their molecular structure permanently.
This extends to other kitchen items you might think are recyclable. Ceramic or oven-safe serving pieces are not recyclable, and decorative tins, sets of pots and pans, and cooking pans are not accepted. The reason? These materials require completely different processing methods than standard recyclables and can actually contaminate glass recycling streams by not melting at the same temperatures.
Contaminated Food Containers and Takeout Packaging
Fast food might be convenient, but those containers are creating a slow-moving recycling disaster. Items with food debris cannot be recycled, and plastic utensils also cannot be recycled. No food or recyclable containers with food residue are accepted, including greasy pizza boxes and clamshells or other plastic containers used to hold takeout food.
The contamination problem is more serious than most people realize. One of the main contaminants in recycling streams is packaging that still contains food and drink, including dirty margarine tubs, half-eaten pots of yogurt, and liquid left in drinks bottles. Food-contaminated items like pizza boxes or aluminum foil are not accepted because food residue attracts pests and contaminates materials, making them non-recyclable. A grease-soaked cardboard takeaway pizza box or food residue from a can of beans can mean that whole lorry-loads of recycling can’t be recycled – a few bad apples spoil the whole barrel.
Medical Waste and Personal Hygiene Items
The pandemic taught us a lot about hygiene, but it also created new recycling nightmares. Hazardous or biohazardous medical waste like batteries can be dangerous when not disposed of properly, and anything used in research or medical fields like syringes, tubing, masks and gloves are medical waste that causes entire recycling loads to be sent to landfill to keep workers safe.
Personal hygiene items present similar challenges. Up to 4000 nappies have to be removed from recycling each day – more than 300 every hour – and they are not only non-recyclable but can spoil other materials and must be removed by hand, which is unpleasant and unhygienic. The contamination factor here isn’t just about processing difficulty – it’s about protecting the health and safety of recycling workers who have to handle these materials manually.
Understanding Contamination’s Broader Impact
The recycling contamination problem isn’t just about individual items – it’s about system-wide failures. Roughly eighty-two percent of citizens are putting non-recyclable items in recycling bins, a slight increase from eighty-one percent in 2023. Wrong or improperly prepared items called contamination may seem recyclable but are unwanted in recycling markets, can place workers at risk, damage sorting equipment, lower the value of recyclable material, and increase program costs.
The municipal solid waste recycling rate in the US remains as low as thirty-five percent, with challenges found in waste stream management where each state, city, and metropolitan area takes different approaches, meaning what can be recycled in one town may be impossible in another. The increased costs of collecting and sorting contaminated recycling are ultimately borne by all taxpayers, making this everyone’s problem.
The scale of the challenge becomes clear when you consider that around 5 million plastic bottles are discarded in the United States every hour, tallying up to 35 billion plastic bottles annually, yet we can’t recycle our way out from under mountains of electronic waste when only twenty-two percent of global electronic waste is recycled, and our social norms of buying, using, and tossing electronics can’t continue at this rate.
What surprises most people about this list? The fact that so many seemingly obvious recyclables actually damage our recycling systems more than they help them.
