Compounds containing hydroxyl groups, which are suitable for the polyisocyanate addition polymerization process, are prepared from polyurethane-polyurea and/or polyurea waste materials. These compounds are produced by reacting a finely divided polyurethane-polyurea and/or polyurea waste material with a low molecular weight diol and/or polyol (and optionally a higher molecular weight polyol) and a low molecular weight urea and/or carbamic acid ester. This reaction may be carried in either one stage or two stages. In the two stage process, the waste material and diol/polyol are reacted in a first stage at a temperature of from about 100 to about 260.degree. C. In the second stage, the amine-containing alcoholysis product obtained in the first stage is reacted with a low molecular weight urea and/or carbamic acid ester. In the single stage process, the polyurethane-polyurea and/or polyurea waste material is reacted with a low molecular weight diol and/or polyol in the presence of a low molecular weight urea and/or carbamic acid ester.