Jug Hand Washer
Use a one gallon jug and a nail. If you are really roughing it, fill a milk jug with water and tie it to a tree by the handle upright. Put a nail in the bottom of the jug. The jug should have a cap on it. When you want to wash your hands, loosen the cap, pull the nail and you have a stream of water. When your done, replace the nail and tighten the cap.