The psychical researchers Eric Dingwall and Harry Price re-published an anonymous work written by a former medium entitled Revelations of a Spirit Medium (1922) which exposed the tricks of mediumship and the fraudulent methods of producing "spirit hands". Originally all the copies of the book were bought up by spiritualists and deliberately destroyed. In 1923, the magician Carlos María de Heredia revealed how fake spirit hands could be made by using a rubber glove, paraffin and a jar of cold water.
The British medium Francis Ward Monck was investigated by psychical researchers and discovered to be a fraud. On November 3, 1876 during the séance a sitter demanded that Monck be searched. Monck ran from the room, locked himself in another room and escaped out of a window. A pair of stuffed gloves was found in his room, as well as cheesecloth, reaching rods and other fraudulent devices in his luggage. After a trial Monck was convicted for his fraudulent mediumship and was sentenced to three months in prison.
In 1880 the American stage mentalist Washington Irving Bishop published a book revealing how mediums would use secret codes as the trick for their clairvoyant readings. The Seybert Commission was a group of faculty at the University of Pennsylvania who in 1884–1887 exposed fraudulent mediums such as Pierre L. O. A. Keeler and Henry Slade. The Fox sisters confessed to fraud in 1888. Margaret Fox revealed that she and her sister had produced the "spirit" rappings by cracking their toe joints.