Good way to save a few kilos

now if only I can figure out how to do this while on a long multiday hike, i wont need to carry so much water with me!
should be able to save me a few kilos easy!
http://www.youtube.com/watch?v=sHeUW-yJihQ
should be able to save me a few kilos easy!
http://www.youtube.com/watch?v=sHeUW-yJihQ