How can you simultaneously save money and the environment? By cutting down on food waste—and taking a few cues from Dana Gunders, a staff scientist at the Natural Resources Defense Council’s Food and Agriculture Program.

About a third of all food produced worldwide is thrown out, according to a report by the United Nations Environment Programme and the World Resources Institute. In America, the number is even higher. Between 30 and 40 percent of our country’s food supply gets tossed, which adds up to more than 20 pounds of food per person every month. And where does this expensive, uneaten food go? Into landfills, which produce methane gases that contribute to global warming.

So instead of tossing out that carton of expired eggs, follow Gunders' lead. NPR’s The Salt recently interviewed Gunders about her new book, Waste-Free Kitchen Handbook. She shared a few tips that will help reduce your carbon footprint—and maximize your grocery budget.

First, if your greens have wilted, don’t dump your spoilt farmer’s market bounty into the trashcan, Gunders advises. Instead, sauté the greens and eat them, or soak them in ice water to make them crisp again. This trick also works for vegetables like broccoli and carrots.

More surprising is her suggestion that expiration dates shouldn't be taken literally. They indicate when a product’s reached peak freshness, not when it’s actually bad to eat. Eggs are still good for three to five weeks after they "expire," and the shelf life of other dairy products, like cheeses, can be extended with wax paper and proper storage techniques.

A little creativity can save brown lettuce and old cheese, but it won’t do much for that leftover quart of milk from two weeks ago, right? Wrong. The tart liquid serves as a substitute for buttermilk and makes fluffy pancakes and biscuits.

When all else fails, skip the refrigerator all together. Instead of reserving your freezer for ice trays and TV dinners, pop in loaves of bread, milk, or unused ingredients from cooking and thaw them out when you need them again.

For more suggestions, read the full interview or check out Gunders' book. 

[h/t NPR]