Place all turkey bones and scraps into a large stockpot
Add sage, rosemary, onions, carrots, celery, crushed garlic, bay leaves, peppercorns, and a small pinch of salt to the pot
Pour in any leftover gravy, turkey drippings, or stock
Fill the pot completely with water to cover all ingredients
Place on low heat and simmer uncovered or partially covered for at least 12 hours, keeping it gentle and avoiding a boil
Carefully lift out the carcass and strain broth through a fine sieve
Let cool and skim excess fat from the top if desired
Store in refrigerator for up to 7 days or freeze for up to 6 months
