Trying to be green and reduce waste backfired on me. Both of my mason jars broke inside my luggage. 🙁 I usually carry at least one jar with me at all times, and they're especially great for travel. They're really versatile and can be used as a water container, to-go coffee cup, to store leftovers, to carry a snack, etc. Sadly, I have no jars for the next month. At least I have my thermos and my reusable utensils, cloth napkins, and reusable bags from home.