Unlike paper and glass, items made of plastic can sometimes be tricky to recycle. In many cases, plastic water bottles should be thrown in the recycling bin intact (not crushed) with the cap left on—but then again, the rules and regulations vary from one recycling center to the next.

Yogurt cups have their own set of challenges, too. According to Lifehacker, many of these containers are made of a polymer plastic called polypropylene (a #5 plastic), which isn’t always accepted by curbside collection programs.

So what should you do with those cups after you’re done enjoying your vanilla Greek yogurt? You can find out what type of plastic the cup is made of by looking at the symbol on the bottom, which contains a number inside of a triangle. For example, Chobani and Yoplait containers are usually made of #5 plastic, which means polypropylene. You can then look up your local recycling program’s rules online to see if that type of plastic is accepted. (In New York City, for example, #5 plastics are accepted.)

If all else fails but you still want to do your part for the environment, you can drop them off at your local Whole Foods, which often participates in a recycling takeback program called Gimme 5 (but call first, since not all locations participate). Alternatively, you can mail them to the Gimme 5 center in Cortland, New York, or use the Recycle More Plastic map to find the closest collection program that’s willing to accept your discarded yogurt cups. Yes, it takes a bit of effort, but it's worth it to make sure that your used container ends up in the right place.

[h/t Lifehacker]