Boil bones for 15 minutes, then add boiled bones, chopped onion, chopped garlic, 1 tbsp. salt and 1 tbsp. of apple cider vinegar to a 4-quart crockpot.
Add 8 cups of water (or enough to cover the bones). Simmer on LOW for 48 hours. If you’re using an Instant Pot, set it to Slow Cook and MEDIUM for 48 hours.
When your broth is done simmering, remove the bones and boiled vegetables.
Strain the broth through a mesh strainer to remove any other bits left behind.
Place broth in a refrigerator to cool for at least 4 hours. The layer of fat will harden on the top.
After the fat has hardened, remove the layer with a spoon. Discard the fat and use your broth to make a tasty soup!