Heat 1/2 pound (two sticks) of unsalted butter in a small, heavy saucepan over low heat. As the butter slowly melts, it will separate into a small amount of milky liquid at the bottom of the pan, a large quantity of clear liquid, and a bit of foamy white residue floating on the top. All you want is the clear liquid, which is the clarified butter. Spoon off the residue from the top and discard it. Without disturbing the white liquid (the milk solids) on the bottom, spoon or pour the clear liquid into another container.
If you have time, you can refrigerate the melted butter until the clarified part is solid. The milk solids, contrary to their name, will remain liquid. Pry the solid clarified butter off and pour away the milky part.