Stranded in the wilderness with an empty canteen? Outdoors expert Keith Hanshaw demonstrates how to make a puddle of muddy water safe to drink with a plastic bottle, a piece of string, and a lighter. Submerge the bottle into the puddle to fill it up and start a small fire with the lighter. Hold your water bottle directly over the flame to bring it to a boil, which will kill all the germs within the bottle. Surely this isn’t the tastiest water you’ll ever drink, but it’s safe, says Keith, and it can save your life.