To keep your roast duck leftovers fresh for that tasty round two, place the duck in an airtight container or wrap it tightly with plastic wrap or aluminum foil. Store it in the fridge if you plan to eat it within 3 days. If you want to keep it for longer, pop it in the freezer—it'll stay good for about 2-3 months. Just make sure you reheat it gently, so it stays juicy and flavorful!