preferred salt due to ease of handling and low cost the salts are made up in a water solution it is most desirable to obtain a multiplicity of microscopic discrete crystals of salt on the surface of each fiber rather than a few large or agglomerated crystals small crystals are obtained by using rapid drying methods using high temperature and high volume air flows fine inert particles such as silica diatomaceous earth high molecular weight starch particles etc may be added to the salt solution so that on application to the fiber nucleating sites for crystallization of the salt are provided this technique helps insure the formation of microscopic discrete crystal domains within the scope of this invention is the use of mixed salts for example with two cations and two anions four different salts are possible the different salts will crystallize separately lessening the chance of large homogeneous crystals the salt solution is preferably added to the fibers by spraying an alternate method is to saturate a pulp fiber board by dipping the pulp fiber board into the salt solution dewatering the board as by suction extraction and drying the board the board is then ground to individualize the fibers and the ground wood pulp fibers collected to form a wood pulp batt the salt domains established on the pulp board by dipping and drying remain adhered to.