Plastic bags are pretty useful for carrying stuff, i keep my loose leaf tea and my museli in separate plastic bags. i'm not sure what natural options i have to be honest, i spose i could use some kind of skrink pot or birch bark container both of which are fun to make and look great on a shelf, but niether are anywhere near as practical as a plastic bag for putting in a back pack. Wrapping things in dock leaves works well for some things when available, and my friend Paul Wylde showed me these amazing leaves that are like cling film in as much as they kind of self adhere and make nice little packagesl, i'll have to ask him what they were called. i've heard Ray Mears uses leather pouches with ziplock plastic bags inside them (an expensive option). i've found ziplock bags made from sheet plastic split along their welded seams, which i guess is why Ray uses a leather pouch to protect it. I just double bag stuff and tie a quick release knot in the top half this provides a good water proof container for free. Like the drinks bottles plastic bags were originally made in separate parts, this created weaknesses where the handle joined the bag. Sten Gustaf Thulin's one piece design with integral handles (the type photographed above) creates a simple, strong bag with a high load carrying capacity. It is manufactured by folding, welding and die-cutting a flat tube of plastic.