Whenever I'm out hiking with Winston (my corgi) I pick up "Treasures."  Really they're just little bits of nature, like an unusually colored leaf, a piece of bark with a hole in it, a dried gourd, or acorns. I fill my pockets and when I get home I empty the contents into a bowl on my desk to await further inspection. Most of the time it ends up in the dust bin, but occasionally a spark of a idea appears.