How Clean Do Your Recyclables *Really* Need To Be?

You may have heard this recycling tip before: only put clean and dry recyclables in your recycling bin. 

But how necessary is this step? If you skip it, your recyclables will still get recycled, right? 

Actually, they might not. The reason why may surprise you — it has a lot to do with the business of recycling. 

Liquids and food left in containers can contaminate not only items in your recycling cart, but also any other recycled materials they come in contact with. True, if you leave a dollop of mayo in the jar or a big swig of soda at the bottom of a bottle, it might not make a huge difference. 

But imagine if everyone on your block did the same thing? Or everyone in your neighborhood? The cumulative effect can ruin otherwise perfect recyclable items. Instead of being recycled, contaminated items will likely end up in a landfill.

By keeping your recycling clean and dry, the city’s program will run more efficiently, and more recyclables will get recycled.    

TL;DR - Cleaning tips

Keeping Recyclables Clean in a Single-Stream Recycling System

Until the 1990s, most U.S. communities used dual-stream recycling. Residents placed their paper and cardboard items in one container and their plastic bottles and metal cans in another. Different trucks, or one multiple-container truck, would pick up the recyclables. Since food and drink containers were separated from the start, it was easier to keep recycled paper and cardboard clean. 

Today, Chicago and most communities in the United States use single-stream recycling. Residents place all recyclables in the same container. Trucks then take the commingled materials to a materials recovery facility, or MRF. There, they’re sorted by type using technology like magnets, screens, conveyor belts, robotics, air jets, and infrared readers. Once sorted, recyclables are formed into giant bales and sold as commodities. 

Take an interactive virtual tour of Chicago’s Blue Cart recycling program, from pickup to MRF to the manufacturers who use Chicago’s recycled items to make new stuff.

Single-Stream Recycling Benefits

Single-stream recycling has many benefits:

  • Increases Participation — More people participate in recycling because it’s convenient. 

  • Lowers Collection Costs — Single-compartment trucks are less expensive than those with multiple compartments. Crews don’t have to sort at the truck, so they can move faster on collection days. 

  • Requires Fewer Truck Trips — With more space, single-compartment trucks can service more households per trip, reducing road wear and tear and CO2 emissions.

  • Easy to Add New Materials — With a single bin and truck for all materials, single-stream recycling makes it easier to update a recycling program without worrying about collection logistics. For example, in 2023, Chicago expanded its recyclable materials to include paper cups

Single-Stream Recycling Challenges

A single-stream system poses challenges, too: 

  • Cross-contamination — Because paper and cardboard are collected alongside other recyclables, if those recyclables aren’t clean of food and liquids, the paper and cardboard can become unrecyclable. 

  • Ease of Recycling Encourages More Waste — Another critique of single-stream and curbside recycling in general is that recycling has become so convenient that we don’t reflect on the amount of waste we produce. Americans are among the most wasteful people on the planet; though the United States accounts for only 4% of the global population, we produce 12% of the world's trash

  • Wishcycling — Since single-stream eliminates the need to sort recyclables into separate bins, wishcycling tends to increase. “Wishcycling” is when optimistic residents add non-recyclable items to the recycling bin. But non-recyclable items placed in a recycling bin don’t get recycled; instead, they end up at the landfill after taking a long, energy-wasting trip through the MRF. 

In Chicago, recycling pickup crews will sometimes tag carts if they see obvious issues like containers filled with food or liquids or if recyclables are contained in plastic bags. But it’s up to all of us to recycle correctly.

Clean Recyclables Help Make Recycling Successful

To understand why it matters if, say, recycled cardboard gets dirty or soaked with liquid, it helps to have some insider knowledge. 

Recycling is an essential part of the U.S. economy. Recycled items are processed into commodity-grade materials, which manufacturers purchase to make new products.  According to the Institute of Scrap Recycling Industries (ISRI), recycling supplies 40% of the raw material needs for American manufacturers.  

Here’s where you come in. It can be nearly impossible for MRFs to sell materials to manufacturers — at market value or at all — if they don’t meet strict quality standards that limit contamination, including food and liquids. 

Here’s an example. The image below shows a 660-pound bale of recycled cardboard. At market value, it will sell for about $35 (as of March 2024). But the bale’s contamination level must be very low: no more than 1%, according to ISRI guidelines

By making sure that the items we put into our recycling bin are clean, we help ensure that our recyclables actually get recycled. 

How Clean? Empty and Clean-ish

Recyclables don't need to be spotless, ensuring they're empty is the key. 

“Recyclables do not need to be perfectly clean to be recycled,”says Joy Rifkin, Sustainability Manager at LRS, Chicago’s recycling partner and processor. But they do need to be empty. “Empty liquids, rinse out plastic containers, and don’t put greasy cardboard or paper in the recycling bin.”

Here are some additional tricks for getting your recyclables clean enough for the bin:  

  • Glass or plastic bottles and aluminum cans (water, soda, wine, beer): Empty all liquids (including water); no need to rinse. 

  • Cartons (milk, juice, broth): Rinse to avoid mold and stench.

  • Cardboard boxes: Remove all packaging materials and flatten boxes to save space.  

  • Greasy cardboard and paper: Tear off the oily parts and recycle the rest.

  • Tubs and jars with sticky food (peanut butter, margarine, jelly): Scrape with a rubber spatula to eliminate the gunk. Got a dishwasher? Stuff sticky containers in an empty corner before running a load.

  • Oily bottles (cooking oil, dressings, sauces, marinades, etc.): Add water, a drop of dish soap, and shake. 

Remember to keep your Blue Cart closed in case it rains. Wet paper and cardboard are tough to sort, and quickly mold.

Less contamination means more recycling success. Next time you rinse out that last bit of ketchup, remember: thanks to you, your recyclables can live on and create something new.

Check Chicago's recycling guidelines for more recycling tips.



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