We like to use an “almost” empty (1.75 G) detergent container to wash our hands outside. We fill it up with stream water and if you use it up just refill it and add a few drops of dish detergent. It’s kept on the edge of the picnic table, out of the way so that the water doesn’t get trekked into the RV. Just make sure to use one with a handle versus the push-button as the latter is a bit difficult to use by yourself. And if you yourself never buy detergent in that size just ask a friend with lots of children – they MUST use it.