I use a 11 inch by 9 issue water proof bag that is OG poly cotton (?) on the out side and either clear pastic or, on the older ones, rubberised on the inside. Theres a two foot cotton tape at the open end for tying it closed. They are 50p or so in the army stores.
I've no idea what they are for but they keep the tinder good and dry.
ATB
Tom
These are great. Big enough to store the natural tinders that you have dried in your pockets.
I store fine ember making tinder like true tinder fungus, char cloth and rosebay willow herb in a oil skin baccy pouch and the birch bark, grasses and bracken in the larger poly cotton bag.
By the way, i'm a fan of flint and steel, but matches are always to hand!