Put all of the bones in a stockpot and add enough filtered water to cover.

Cook on high until the water comes to a boil and scum rises to the top. Cook for 5 minutes.

Dump the entire pot of water and refill with fresh filtered water, enough to cover the bones. Mix in the apple cider vinegar and bring the water to a boil once again.

Carefully skim off any foam that comes to the top. It should be minimal given that the water with most of the scum was dumped in the previous step.

Reduce heat and simmer on low for 9-24 hours.

Remove the pot from the heat, strain and taste. Add salt and pepper as needed. Let cool and then refrigerate in one or more airtight containers.

Skim the lard off the top of the chilled pork broth the following day and refrigerate. Reserve this delicious fat high in Vitamin D for cooking. This article plus video provides more information on how to render lard.

Use the clarified pork stock as the base for soups and sauces the same as you would use chicken or beef stock.