Tear off 4 pieces of aluminum foil big enough to enclose each portion of ribs. Spray each piece of foil with vegetable cooking spray. Brush the ribs liberally with barbeque sauce and place each portion in its own piece of foil. Wrap tightly and refrigerate for at least 8 hours, or overnight.
Preheat oven to 300 degrees F (150 degrees C).
Bake ribs wrapped tightly in the foil at 300 degrees F (150 degrees C) for 2 1/2 hours. Remove from foil and add more sauce, if desired.