During the holidays, I make this a lot. I save the court-bouillon for re-use, and clarify it between uses with an egg white and shell. The next time I poach a salmon, I strain the court-bouillon and top it up with more white wine. Over a week the court-bouillon becomes very flavorful.

To save the court-bouillon, bring it to a boil and put it into a hot glass mason jar just large enough to hold it. Store in the refrigerator. The top should pop down indicating a good seal.

To clarify the court-bouillon, put the cold court-bouillon into a large pot along with one lightly-whipped egg white and the crushed shell. Bring to a low boil, stirring. When it reaches the boil, reduce the heat and let it simmer very lightly for 10 minutes. The egg white will collect impurities and form a scum on the surface. After 10 minutes, turn off the heat and let it sit undisturbed for 10 minutes more. Strain through cheesecloth and bottle into a hot mason jar. Store in refrigerator.

(This tip from Jane Grigson's Charcuterie.)