A process for the purification of a crude polyether polyol is provided, where the crude polyether polyol is prepared by anionic polymerization of alkylene oxides in the presence of basic catalysts. The process includes neutralizing of the catalysts with mineral acid to form a salt, addition an adsorption agent and/or filter aid and removing the salt and adsorption agent and/or filter aid by filtration to form a filter. In a subsequent step, the filter cake is pressed to recuperate the polyether polyol.