Character Analysis
Steinlauf is another of Primo's friends, an older man of 50. He's Hungarian, had served in the Austro-Hungarian Army, and was even awarded the Iron Cross (a prestigious medal).
Early on during Primo's time at Auschwitz, Steinlauf emphasizes the importance of staying clean, even though the water in the washrooms is filthy, and the prisoners themselves will almost certainly become dirty again shortly after washing up. Initially, Primo doesn't want to waste his time, but he later learns what Steinlauf is suggesting by this:
[T]hat precisely because the Lager was a great machine to reduce us to beasts, we must not become beasts; that even in this place one can survive, and therefore one must want to survive, to tell the story, to bear witness; and that to survive we must force ourselves to save at least the skeleton, the scaffolding, the form of civilization. (3.12)
Keeping oneself clean, even though it's very temporary, is part of this "scaffolding" of civilization, Steinlauf believes.
Steinlauf teaches Primo his most important lesson: that even though the Nazis are trying to reduce them to animals, and that they may not be able to do much about that while in the camp, they can at least quietly rebel by continuing to behave like men and not consenting to being defined as subhuman.