A cyclic urea reaction product forms as a by-product of a hindered amine acid gas scrubbing process and results in an ultimate buildup of the material in the circulating amine scrubbing solution. The buildup of this material has a deleterious effect on acid gas removal rates and accordingly, results in inefficient acid gas removal. In the process of the present invention, the cyclic urea degradation product is removed from the circulating solution by employing a selective precipitation of the cyclic urea followed by filtration. The selective precipitation is carried out by cooling the circulating solution to a particular temperature level such that the cyclic urea comes out of solution while the other components remain in solution.