A fat separator is a very useful and easy-to-use tool in cooking. The common fat separator is a large glass cylinder much like a measuring cup with a handle on one side and a long spout coming from the bottom of the other side. Pour your broth into the measuring cup part of it. You will notice the fat collect on the top. Pour out a small amount using the spout to get rid of the fat on it. Then pour the broth out the spout steadily. You must stop before the fat collected on top has a chance to reach the spout. It is best to pour all the broth that you will use in one motion, rather than several. You should also read our articles on broth and basters.