A process for obtaining a polyol-containing homogeneous liquid composition, which can be directly reused as a polyol component for the production of rigid polyurethane foam, from a rigid polyurethane foam, which comprises treating said foam at a temperature of from 150.degree. to 220.degree. C in the presence of a mixture of (a) an aliphatic diol having 4-7 carbon atoms and having a boiling point higher than 160.degree. C and (b) a monoalkanolamine having 2 to 8 carbon atoms, the amount of said monoalkanolamine (b) present in said mixture being within the range of from 1 to 20 percent by weight.