The invention relates to a device and method of using the device and plastic injection molding processes. A mold is provided utilizing a core inside the injection cavity of the mold. The core is prior to insertion of the mold subjected to a sub-freezing atmosphere. The core is then placed in the mold cavity wherein is injected the plastic material to mold the plastic part substantially surrounding the core. A thin film of air is formed around the "core" at the time of the injection of the plastic material thereby providing a substantial increase in surface finish to the plastic molded part. The core is made from a material which when heated will melt prior to the melting of the plastic part so that the core and part are removed from the cavity and subjected to a heating step thereby enabling removal of the core from the part.