Place pork roast in slow cooker. In a medium bowl, mash cranberry sauce; stir in sugar, cranberry juice, mustard and cloves. Pour over roast. Cover and cook on low for 6 to 8 hours or until meat is tender. Remove roast and keep warm. Skim fat from juices; measure 2 cups, adding water if necessary, and pour into a saucepan. Bring to a boil over medium-high heat. Combine the cornstarch and cold water to make a paste; stir into gravy. Cook and stir until thickened. Season with salt. Serve with sliced pork.