Once you’ve used up that jar of pasta sauce (and added these tasty mix-ins to make it taste homemade) or emptied out that tub of sour cream, it can be tempting to want to reuse these containers. Some of these jars are the perfect size for storing dry goods or are good to have on hand for sending leftovers home with friends. But I’ve been curious: Is it safe to reuse food containers over and over again (or should they just be recycled)?
The verdict on glass containers
Good news for folks that reuse glass bottles and jars: You’re in the clear. Glass is safe to repurpose indefinitely as long as it’s cleaned between uses. Just be aware that the lids that come with these jars won’t be absolutely air-tight, so they won’t be suitable for canning—but they’ll work just fine for food storage.
If you have leftover mason jars from jams and jellies, you can give them new life with our favorite recipes made in a jar.
But what about plastic?
When it comes to plastic, however, it isn’t so cut and dried. Different types of plastic are created for different uses, so before you think about wrapping up your leftovers in that second-hand container be sure to check the bottom for the kind of plastic. You’ll see all plastic products are labeled with the recycling symbol with a number—from one to seven—inside.
If your container is made of plastic #1, or polyethylene terephthalate (PET), you shouldn’t reuse it according to the Sierra Club’s plastic guide—instead just recycle these containers. Similarly, plastics #3 and #6 (#6 is styrofoam) should not be reused—they also cannot be recycled. Also be sure to double-check any #7 plastic you have at home because it may contain BPA which can be bad for your health according to the National Institute of Environmental Health Sciences.
The safest plastics to reuse at home are plastics #2, #4 and #5. Each of these is safe for storing food and can be reused until they start to show signs of wear. If you find that your plastic containers—be they from food packages or storage containers you buy at the kitchen store—start to scratch or discolor, it’s best to recycle them to prevent any chemicals leeching into your food.
Can you microwave them?
When it comes to your glass containers, they are safe to microwave. However, there isn’t a blanket policy for plastic containers. If you’re looking to microwave a reusable container like a piece of Tupperware or Gladware, it’s best to check what the manufacturer recommends. If you’re planning on reheating your favorite leftovers in a repurposed to-go container, you might want to think twice.
Harvard Medical School recommends that no food should be reheated in repurposed plastic containers since those to-go boxes and margarine tubs are designed for one-time use (and could potentially leak bad-for-you chemicals when exposed to high heat).
The definitive answer
It’s safe to say that it’s OK to use glass containers over and over—plus, good on you for recycling! Reusing plastic, though, is a lot tougher and requires a little bit of investigation and a lot of consideration, especially if you want to pop it in the microwave. If you don’t want to worry about how to repurpose plastic, try going plastic-free like one of our staffers! She has plenty of eco-friendly tips.