The Sonderkommando were Jewish prisoners who were forced to perform work duties around the gas chambers and crematoria at the extermination camps. Their duties included instructing those victims what to do as they entered the gas chambers, emptying the gas chambers of bodies, searching victims for valuables, removing gold teeth, and working in the crematorium to burn the bodies. Sonderkommando are often associated to Auschwitz-Birkenau, although others were also used in other extermination centres. The Sonderkommando were killed after a few months and replaced as a way to hide the evidence of the Nazis crimes. In 1944, the Sonderkommando at Auschwitz-Birkenau held an uprising and destroyed one of the crematoria.