74 the grain of the paperboard in the base blank 20 extends parallel to score lines 38 and 54 the grain of the paperboard in the top blank 76 extends parallel to score lines 88 and 90 with the grains running in these directions the extensions 46 48 50 and 52 and the panels 80 and 82 tend to remain flat with the grains running perpendicular to the preferred direction the extensions 46 48 50 and 52 may tend to become wavy thus adversely affecting the seal between the top and the base referring to fig1 and 4 6 the base blank 20 is folded along score lines 64 40 42 and 44 to form a sleeve with the inner polyethylene coated surface of base side panel 28 adjacent its free edge overlapping the polyethylene coated flap 66 the inside surface of panel 62 and the non skived outside surface of flap 66 are heat sealed to the inner surface of the base side panel 28 as shown in fig1 to form the sleeve shown in fig4 the side seam of the sleeve has no raw edges to permit moisture migration and the bond between the inside polyethylene coated surfaces forms a vapor proof seal as shown in fig1 only inner coated surface of panel 66 and fold line 63 are presented to the inside of the package thus wicking of moisture from exposed edges such as edge 65 is prevented wicking occurs because uncoated paperboard edges tend to absorb moisture and carry it through the paperboard fibers and onto the package after the sleeve is formed the sealing extensions 46 48 50 and 52 are.