Can I use dry ice in a cooler for camping or shipping food?

Yes, you can — dry ice keeps things frozen much longer than regular ice and leaves no water mess. But you need to be careful: it’s -109°F, so put cardboard between it and cans or glass to prevent bursting, and vent the cooler slightly to avoid CO2 buildup that could blow the lid off. Never touch dry ice with bare skin — use thick gloves — and don’t store it in a sealed car or small room, as CO2 can displace oxygen. It’s a pro move, but requires planning.