You now might use saltpeter if you want an old stump in your yard to decompose faster, but for a millennium it was the cause of wars, massacres, and great grassroots scientific efforts. It changed the history of the world.
Remember the burning bat signal in The Dark Knight Rises? Wasn't it cool? Now you can do a miniature version of it, only on a piece of paper instead of a bridge. Paper is far more portable, anyway.