Abstract: A process for removing troublesome precipitates of condensable gases in a heat exchanger of a continuously operated low temperature installation in which gas to be cooled, such as air, which contains condensable gases at ambient temperature is passed from a warm end to a cold end of the exchanger through a storage material and over heat exchange surfaces--maintained at a temperature ranging from -165.degree. C. to -160.degree. C. at the cold end--and cold regenerator gas free of condensable gases is alternately passed from the cold end to the warm end over the storage material and heat exchanger surfaces to remove precipitates of the condensable gases therefrom in a cyclic operation, without total shut-down of the installation, involves the further step of introducing warm gas which is at a temperature of between 0.degree. C. and +110.degree. C.