In A Small Saucepan, Combine The Juice, Jelly, Ketchup And Tomato Sauce. Cook And Stir Over Medium Heat Until Jelly Is Melted; Remove From The Heat. Place Meatballs In A 5-Qt. Slow Cooker. Pour Sauce Over The Top And Gently Stir To Coat. Cover And Cook On Low For 4-5 Hours Or Until Heated Through.