Back in 1972 the HWE process was not only a new process but also relatively unknown to most. I clearly remember making a sales appointment with the husband and wife to explain how the wand works; water is sprayed here and extracted there, and........so on!
The use of a Defoamer/Anti-Foam product was almost a necessity on the majority of carpets too!
Glad those days are long gone even tough I do have pleasant memories
The JAGUAR MX-2 ETM @ cross-american.com