Single ply paperboard containers are wax-coated by directing a relatively narrow spray band of atomized wax towards the interior surfaces of the containers being treated. The spray band is volumetrically asymmetrical and is oriented relative to the interior surfaces of the container such that its volumetric asymmetry is directed towards the bottom circumferential seam between the tubular side wall and bottom wall of the containers. In this manner, a minimal (but fluid-impervious effective) nonsaturating amount of wax will be applied to the interior surfaces of the container so as to preserve the vivid appearance of color graphics and/or indicia that may be printed on the exterior surface of the container. At the same time, the volumetric asymmetry and orientation of the spray band ensures that a maximum amount of wax will be applied at or near the circumferential bottom seam so that a fluid-impervious fillet seal may be established thereat. The appearance of the color graphics and/or indicia may optionally be further improved by the electrostatic spray application of a suitable lacquer. The applied lacquer, when dried, will thereby enhance the "glossy" exterior appearance of the interior wax-coated containers.