These are small gas-chambers, designed to exterminate vermin, mainly lice, a population that thrived in Birkenau. There were many of these chambers, operated by prisoners, in the Sauna. They were placed in the wall, with a room on either side; one side was dirty, the other, clean. Ex-prisoner Manya Buki, worked here gassing vermin in the clothes of new arrivals. "Vermin" was also a term used by Nazi propagandists to describe the Jews. It is easier to kill people seen as insects. This term, "vermin", used by Nazi theoreticians, propagandists and camp officials to consciously desensitize those ordered to commit murder. Mrs. Buki also did this to prisoner's uniforms, while they waited outside, sometimes all day in freezing weather. The irony of it: a Jewish women using Zyclon B, the same gas used to exterminate people, gassing actual "vermin" in Birkenau.