Place duck carcasses in a large stockpot. Break up the bones into pieces if necessary to fit the pot.

Add enough cold filtered water to cover.

Add a small amount of store bought or homemade apple cider vinegar. 1/4 cup works well. Stir. *If you only have a stainless steel stockpot, leave out the ACV as it can potentially leach nickel from the pot. Ceramic or clay stockpots are best for broth.

Leave on the counter for 30 minutes per French culinary practice.

Place stockpot on the heat and bring to a boil. Skim off and discard any foam (off flavors and impurities) that rise to the top just before boiling is reached. 

Add optional cooked giblets with juices and chopped veggies, and then turn the heat down to low, cover, and let simmer for 3 hours for low-glutamate stock and 8-24 hours for more flavorful bone broth.

Remove from heat, cool, and strain into large 1/2 gallon mason jars or containers of choice. Place the strained fat in a separate glass container with a tight-fitting lid.

Refrigerate clarified duck broth for up to 5 days and use as desired for sipping or as a base for soups/sauces. Freeze what you will not use during that time.

Refrigerate strained duck fat for several weeks to a month or two. Recommended use is for roasting vegetables or making healthy duck fat, French fries.