Testimony was given both by Nazis and by British prisoners of war about the development of an industrial process for producing soap from human bodies , the production of such soap on a small-scale basis , and the actual use of this soap by Nazi workers at the Danzig Anatomic Institute . Testimony was given both by Nazis and by British prisoners of war about the development of an industrial process for producing soap from human bodies , the production of such soap on a small-scale basis , and the actual use of this soap by Nazi personnel at the Danzig Anatomic Institute .