To use confit, set the storage crock in a warm room or place in a deep pan of warm water until the fat is softened, 2 to 4 hours. Take out as many pieces as you need and set aside. Make sure the remaining pieces are well covered with fat; add peanut oil or melted lard, if necessary.
For safety, all confit should be heated through before serving, even for dishes to be served cold or at room temperature. If your dish does not require a crisp skin, steam the pieces for 10 minutes over boiling water or heat slowly in the oven. This steaming, which softens the preserved duck, also removes excess fat.