Storing Ideas:Refrigerate. Store them in an air-tight container for up to 10 days. Freeze. Store the leftover cranberry relish in freezer-safe air-tight bags or containers for up to 4 months. To thaw, let them in the refrigerator overnight. Reheat. It tastes good when it is at room temperature. You may gently warm it over the microwave or on the stovetop.