Soap made by human corpses

 In the 20th century, there have been various alleged instances of soap being made from human body fat. During world war 2, it was believed that soap was being mass produced from the bodies of the victims of concentration camps located in Poland.
The Yad Vashem Memorial has stated that the Nazis did not produce soap from Jewish corpses on an industrial scale, saying that rumors that soap from human corpses was being mass-produced and distributed were used by the Nazis to frighten camp inmates.
Evidence does exist, however, which indicates the possibility that German researchers had developed a process for the industrial production of soap from human bodies.
 Germany suffered a shortage of fats during World War II, and the production of soap was put under government control. The "human soap" rumours may have originated from the bars of soap being marked with the initials RIF, RIF soap was a poor quality substitute product that contained no fat at all, human or otherwise.

20th century soap

 A laboratory assistant at the Danzig Anatomical Institute, testified that soap had been made from corpse fat at the camp, and claimed that 70 to 80 kg of fat collected from 40 bodies could produce more than 25 kg of soap.
The recipe making soap from human bodies:
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.

Human soap evidence