Put beef in 5 quart slow cooker. Mix tomato sauce, next 5 ingredients and if desired, cinnamon and cloves; pour over beef.
Cover and cook on high 1 hour; reduce heat to low and cook 7 to 8 hours. Remove beef from slow cooker. Shred with 2 forks. Return beef to slow cooker and stir into sauce. Serve on buns. Makes 12 servings.