Humans cause nearly 85 percent of wildland fires in the United States, according to the Forest Service. One of the culprits? Campfires that aren’t completely out. Letting your post-s’mores logs burn down unsupervised isn’t safe—you’ve got to douse them with water until the coals are cool. I called up Gwen Beavans, national fire-prevention program manager with the U.S. Forest Service, for her tips on how to snuff out your flames the right way.