The baggy can duplicate as a source of water by tying it over a leafy branch, evaporations and condensation will draw drinkable water ( no need to filter or purify) from the branch. <img src="/ubbthreads/images/graemlins/thumbup.gif" alt="" />
A tip for those who want to carry bags for this purpose is to use the thin plastic fruit/vegetable bags that you get free at the grocery to put your produce in. They are food grade plastic, and because they're so thin, you can compact several in a very small space. They're also free, which is another bonus.
