Cooking lore is chock-full of arcane techniques like larding, barding, and fining—things you dutifully learn and then, like algebra, promptly forget. Here's a simple way to clarify a stock: Stir beaten egg whites into simmering broth. Stop stirring and the egg whites will rise to the surface, forming—you guessed it—a raft. As it bubbles, the raft attracts all stray particles.