2. Heat the oil in a large pot or Dutch oven over medium-high heat. Sauté the onion, carrot, and celery for about 5 minutes. Add the garlic, thyme, and cloves, along with more salt and pepper, and cook for another minute. Add the trimmings, bones, and skin, and cook for an additional minute, stirring. Pour in the stock and wine and bring to a boil. Reduce the heat to low, and simmer, uncovered, for about 2 hours, or until the mixture is reduced to about 2 cups. Occasionally skim fat from the surface. Strain the sauce, discarding the vegetables and trimmings, and return the sauce to a gentle simmer.