Soap made from human corpses

During World War II, many people thought that the Nazis were making soap from the bodies of Jewish people who died in the concentration camps.
The Yad Vashem Memorial has said that the Nazis did not make a lot of soap from Jewish bodies. Yad Vashem says that the Nazis used rumors about making soap from bodies to scare the camp inmates. However, there is evidence that research facilities had come up with a way for large amounts of soap to be made from human bodies.
History.
World War I.
During World War I, the British had already accused Germany of using the fat from human bodies to make things. In April 1917, an important newspaper in London, England called "The Times" wrote that the Germans were using the bodies of their own dead soldiers to make soap and other products. It was not until 1925 that the British Foreign Secretary, Sir Austen Chamberlain, officially said that the "corpse factory" story had been an error.
World War II.
Stories that the Nazis made soap from the bodies of concentration camp victims were common during the war. Germany did not have enough fats to make soap during World War II. Because of this, the government took control of making soap.
The "human soap" stories may have started because with the bars of soap made by the government were marked with the initials "RIF." Some people thought this stood for "Reichs-Juden-Fett" in German. This means "State Jewish Fat" in English. (In German acronyms, "I" and "J" were often used like the same letter, so people thought "RIF" could mean "RJF".)
In fact, "RIF" actually stood for "Reichsstelle für Industrielle Fettversorgung." This was the German government agency in charge of making and giving out soap and washing products during the war. (In English, the agency's name was the "National Center for Industrial Fat Provisioning.") RIF soap was not very good, and did not have any kind of fat.
Raul Hilberg reports that stories about soap made from human fat were told in Lublin, Poland, as early as October 1942. The Germans themselves knew about the stories. Heinrich Himmler, the leader of the SS, got letter saying the Poles thought Jewish people were being "boiled into soap." The letter also said the Poles feared they would also be used to make soap. These stories were so widely known that some Polish people actually refused to buy soap. Himmler was so worried by the rumors, and the thought of poor security at the camps, that he said that all bodies should be burnt or buried as quickly as possible.
Soviet propagandist Ilya Ehrenburg reported a common version of the story as fact in "The Complete Black Book of Russian Jewry":
Evidence of soap-making at Stutthof.
During the Nuremberg Trials, Sigmund Mazur, a laboratory worker at the Danzig Anatomical Institute, said that soap had been made from the bodies of dead people at Stutthof concentration camp. He said that 70 to 80 kg of fat collected from 40 bodies could make more than 25 kg of soap. He also said that the finished soap was kept by Professor Rudolf Spanner.
Mazur gave a recipe that read: "5 kilos of human fat are mixed with 10 liters of water and 500 or 1,000 grams of caustic soda. All this is boiled 2 or 3 hours and then cooled. The soap floats to the surface while the water and other sediment remain at the bottom. A bit of salt and soda is added to this mixture. Then fresh water is added and the mixture again boiled 2 or 3 hours. After having cooled, the soap is poured into molds." 
At the Nuremberg Trials, Nazi witnesses and British prisoners of war supported Mazur's story. (The British prisoners of war had been used as forced labor to build the Stutthof camp.) These witnesses talked about seeing:
After doing research, Holocaust survivor Thomas Blatt found little evidence of mass production of soap from human fat. However, he found evidence that soap had been made from human fat in experiments. Holocaust historian Robert Melvin Spector agrees that the Nazis "did indeed use human fat for the making of soap at Stutthof," but in small amounts.
In his book "Russia at War 1941 to 1945", Alexander Werth said that while visiting Danzig in 1945 just after it was freed by the Red Army, he saw an experimental factory outside the city for making soap from human bodies. Werth said that it had been run by "a German professor called Spanner" and "was a
nightmarish sight, with its vats full of human heads and torsoes pickled in some liquid,
and its pails full of a flakey substance - human soap".
Postwar.
After the war, in 1955, Alain Resnais included the idea that the Nazis made large amounts of "human soap" in his Holocaust documentary movie "Nuit et brouillard". After the war, some Israelis also spoke about Jewish victims of Nazism with the Hebrew word "סבון" ("sabon", "soap").
Mainstream Holocaust scholars think the idea that Nazis made large amounts of "human soap" is part of WWII folklore. Examples of scholars who believe this include the well-known Jewish historians Walter Laqueur, Gitta Sereny, and Deborah Lipstadt. Other people who believe this include Professor Yehuda Bauer of Israel's Hebrew University, and Shmuel Krakowski, archives director of Israel's Yad Vashem Holocaust center. Historian Yisrael Gutman agrees that "it was never done on a mass scale." And Holocaust historian Robert Melvin Spector says that the Nazis "did indeed use human fat for the making of soap at Stutthof," but in small amounts.
Today Holocaust deniers use this story to make people doubt the Nazi genocide.
Play.
"The Soap Myth" is a 2009 play about Nazis making soap from the bodies of the people they murdered.