It sounds like the simplest task: place materials that can be recycled into bins separate from your usual trash, so that they can be repurposed down the line.

But are jar lids recyclable? Is there a difference between a greasy pizza box and a clean one? Can you throw a broken drinking glass in the bin along with glass bottles?

The devil is in the details. And those details differ from city to city. No wonder a recent study by the Grocery Manufacturing Association found that 92% of respondents were unclear about what they should put in the recycling bin.

How should you approach the task? Here are some broad guidelines, suggested by the recycling company Roadrunner:

DON’T… 

Assume if there’s a recycling code on a product that your area will accept them. “Only two (PETE #1 and HDPE #2) of the seven plastic resin codes are widely accepted by most curbside recycling programs,” notes Roadrunnner. “To-go coffee cups, plastic bags, and Styrofoam are among the products that have recycling symbols on them, but are not recyclable” in most curbside programs.

Discard greasy pizza boxes in recyclable bins: The oils can’t be separated from the cardboard fibers; thus, these pizza boxes aren’t recyclable.

Don’t flatten aluminum cans or plastic bottles: While this was previously encouraged to maximize space in recycling bins, now recyclers urge customers to leave them intact, as new, high-tech sorting equipment identifies containers by shape and other characteristics.

Try to recycle yard waste or organics: They are not recyclable and will contaminate true recyclables in the bin. Compost them instead.

Place window glass, vases, stemware and drinking classes in your recycling cart. They are different from jars and glass bottles and will contaminate the bin. Only discard the latter. And remember that large metal lids from glass jars are recyclable, but should be removed from the jars before putting them in the cart.

DO…

Take plastic bags to the grocery store for recycling: “Thin plastics like grocery bags tend to clog up recycling equipment at processing facilities,” reports Roadrunner.  “They require special recycling capabilities that many recycling facilities are not set up for.” Grocery stores will take your bags for proper recycling. And don’t forget that reusable bags are the best idea of all.

Sort your recyclables: This allows the other items to remain uncontaminated on the way to the recycling facility, “making it easier and more efficient for materials to be processed,” said Roadrunner.

Breakdown cardboard boxes: This helps maximize container space and reduce trips for trash collectors.

Empty all food and beverage containers and rinse them clean. Otherwise, they will contaminate all of the recyclables in any bin.

Check your city website to understand the requirements of your local recycling program. For Denver’s rules, click here. Then click on the “Recycling” tab, then “What Can be Recycled.”