A display pack for a consumer product is made of two sheets of corrugated cardboard and a clear plastic container with a flat insertion portion sandwiched between the cardboard sheets. The two cardboard sheets are adhered together in a peripheral area of the package by a heat-sensitive adhesive, and the corrugations of the cardboard sheets are crushed and flattened in the peripheral area. To seal the package, the peripheral area of the two cardboard sheets is subject to sufficient pressure to crush the corrugations inside the cardboard sheets and flatten them in that area. Heat is applied to the outer side of the cardboard sheets in the peripheral area and conducted to the adhesive material between the two sheets to activate the adhesive material. A sealer machine with a heated sealing press or parallel sets of heated rollers may be used to carry out the sealing process.