A method for preparing polyether polyols, wherein the method comprises the steps of: a) providing a crude polyether polyols mixture comprising polyether polyols and a base catalyst; b) mixing the crude polyether polyols mixture with an aqueous solution of an acid thereby neutralizing said base catalyst and providing a neutralized polyether polyols mixture; c) removing at least part of the water from the neutralized polyether polyols mixture, thereby providing a dehydrated neutralized polyether polyols mixture comprising polyether polyols and a suspension of the crystallized salts suspended in the polyether polyols, which salts result from the neutralization of the base catalyst by the acid; d) separating the polyether polyols from the crystallized salt by filtration resulting in a filtration cake comprising crystallized salts and remaining polyether polyols around the crystals; e) removing at least part of the polyether polyols from the filter, leaving a filtration cake; f) redissolving the filtration cake obtaining a mixture of a salt solution and the remaining polyether polyols; g) separating the remaining polyether polyols from the salt solution, by density difference between the remaining polyether polyols and the salt solution, forming at least two layers, the salt solution layer and the polyether polyols layer, wherein the salt solution layer comprises a salt concentration that is sufficient to provide phase separation, wherein the polyether polyols layer comprises at least two layers, a gummy layer and a pure polyether polyols layer; h) removing at least part of said pure polyether polyols layer and leaving the gummy layer and the salt solution layer. a) providing a crude polyether polyols mixture comprising polyether polyols and a base catalyst; b) mixing the crude polyether polyols mixture with an aqueous solution of an acid thereby neutralizing said base catalyst and providing a neutralized polyether polyols mixture; c) removing at least part of the water from the neutralized polyether polyols mixture, thereby providing a dehydrated neutralized polyether polyols mixture comprising polyether polyols and a suspension of the crystallized salts suspended in the polyether polyols, which salts result from the neutralization of the base catalyst by the acid; d) separating the polyether polyols from the crystallized salt by filtration resulting in a filtration cake comprising crystallized salts and remaining polyether polyols around the crystals; e) removing at least part of the polyether polyols from the filter, leaving a filtration cake; f) redissolving the filtration cake obtaining a mixture of a salt solution and the remaining polyether polyols; g) separating the remaining polyether polyols from the salt solution, by density difference between the remaining polyether polyols and the salt solution, forming at least two layers, the salt solution layer and the polyether polyols layer, wherein the salt solution layer comprises a salt concentration that is sufficient to provide phase separation, wherein the polyether polyols layer comprises at least two layers, a gummy layer and a pure polyether polyols layer; h) removing at least part of said pure polyether polyols layer and leaving the gummy layer and the salt solution layer. <EOS>