The solution: Skim smarter. Move the soup pot halfway off the burner every 15 minutes or so, and skim from the edge that's tilted off the heat. Impurities and fat gather at the coolest spot—in this case, the side of the pan off the burner. Tilt the pan slightly as you skim to avoid taking off too much broth. Simmer the soup gently, and never boil: That just churns fat into the broth, making an oily, unappetizing emulsion. If time allows, chill the soup overnight. Fat will solidify on top; simply spoon it off before you reheat.