To make the stock: Place reserved bones, etc., in one layer in a large stockpot with the oil. Brown over high heat for 5 minutes. Reduce heat to medium and brown for 20 minutes. Drain and discard fat. Add onion, carrots and 4 qt. water to stockpot. Stir in celery, garlic, tomato paste, bay leaf, and thyme. Bring to boil over high heat. Reduce heat and boil gently for 3 to 3-1/2 hours. Strain. Should have 4 cups.
