Skimming

Skimming removes a small amount of unwanted material, most often fat, foam or scum, from the surface of a cooking liquid such as a stock, broth, soup or sauce, and from the coagulated film that forms when milk or other liquids are heated. A plastic bulb baster or the edge of a large spoon can lift material off the surface, but the recommended method drags a paper towel, held by one edge, across the surface of the liquid to absorb the unwanted film, with a fresh pass of the same towel repeated as needed.