Abstract: A four-sided, sift-proof carton and method of sealing the end flaps of same includes two minor flaps and an inner and outer major flap at the top and bottom of the carton. The inner and outer major flaps are each formed with a width less than the depth of the carton so that when folded a space or gap is formed beneath the outer major flap between the leading edge of the inner major flap and the fold line of the outer major flap. A sift-proof seal is formed between the flaps by applying ribbons or strips of foamed hot melt adhesive along the outer ends of the inner major flap which is folded atop the minor flaps, and by applying strips of foamed hot melt adhesive in a block C shape onto the ends and middle of the outer major flap which is folded atop the minor flaps and inner major flap.