A method of hardening wooden flooring blanks by impregnating the wooden flooring blanks with a hardener while the wooden flooring blanks are in a bundle, wherein the bundled hardened wooden flooring blanks have improved separation characteristics following completion of the impregnation treatment. The method includes the steps of assembling a plurality of wooden flooring product blanks into a bundle of blanks in surface-to-surface contact with each other and enclosing the wooden flooring blanks in a pressure vessel. The pressure vessel is evacuated and an effective quantity of a hardening composition for being impregnated into the wooden flooring blanks is introduced into the pressure vessel. An effective quantity of a polyethylene glycol composition is introduced into the pressure vessel. The wooden flooring blanks are soaked in the hardening composition and the polyethylene glycol composition for a predetermined period of time. Increased pressure is applied to the wooden flooring blanks to drive the hardening composition and the polyethylene glycol composition into the wooden flooring blanks. The impregnated flooring blanks separate from each other without damage to the exposed surfaces. Stability of the blanks is enhanced.