Bone Broth

Bones: for beef and lamb use knuckle bones, ideally. Can also use fish heads (not that brave) and chicken bones.
Cover bones with water.
Add 2 tablespoons of vinegar per quart of water.
Vegetables such as carrots, celery, and onions can be added to soup stock.

Let stand for 30-60 minutes. Bring the pot to a boil and then reduce heat to a simmer. Remove any scum at the top of the broth with a spoon. Simmer minimum 6 hours. (Ideally simmer for 24-48 hours? Try a crock pot.) Strain the broth.

From How to Cure Tooth Decay, though I hate to admit it.