Each extermination camp operated differently, yet each had designs for quick and efficient industrialized killing. While Höss was away on an official journey in late August 1941 his deputy, Karl Fritzsch, tested out an idea. At Auschwitz clothes infested with lice were treated with crystallised prussic acid. The crystals were made to order by the IG Farben chemicals company for which the brand name was Zyklon-B. Once released from their container, Zyklon-B crystals in the air released a lethal cyanide gas. Fritzsch tried out the effect of Zyklon B on Soviet POWs, who were locked up in cells in the basement of the bunker for this experiment. Höss on his return was briefed and impressed with the results and this became the camp strategy for extermination as it was also to be at Majdanek. Besides gassing, the camp guards continued killing prisoners via mass shooting, starvation, torture, etc.