Imagine a coworker asks to borrow your toothbrush since she left hers at home. You'd be disgusted! So why are earbuds any different?
Studies have found that people who frequently use earbuds have substantially more bacteria in their ears than those who rarely use them. That makes total sense when you think about all the germs earbuds pick up as they go from your pocket to your ear to your bag and back to your ear. Plus the natural moisture and heat from your ear canal is a prime environment for bacteria to multiply.
Before you swear off earbuds for good, there are a few ways you can mitigate the microbial problem. First and foremost: Don't share them! It's a surefire way to introduce earwax that isn't yours. If you must share, disinfect them with a cotton ball dampened with disinfecting spray or rubbing alcohol before you use them again. In fact, you should clean your earbuds at least once a week whether you share them or not. And be sure to store them in a clean, dry place.