I remeber reading a reason behind cutting the hairs of prisioners and removing any metal dentures in their tooth before they entered the gas chamber to maximize the suffering or something, could someone explain the reason behind it, if it all there is one ??
/u/commiespaceinvader has answered a version of your question about hair as well as Why did the Nazis not use neutral gases such as helium in gas chambers?. I also urge you to read his essay "The children will go bathing" -- on the study of cruelty.
/u/estherke has previously explained the various revenue streams of the Holocaust, touching briefly on hair and found primary source documentation for where the hair went.