The `` human soap '' stories may have started with the bars of soap being marked with the initials RIF , which was interpreted by some as Reichs-Juden-Fett ( `` State Jewish Fat '' ) ; in German acronyms , `` i '' and `` j '' were often used for either letter . The `` human soap '' rumors may have originated from the bars of soap being marked with the initials RIF , which was interpreted by some as Reichs-Juden-Fett ( `` State Jewish Fat '' ) ; in German acronyms , `` i '' and `` j '' were often used interchangeably ( in German Blackletter , a k a Fraktur the difference is only in length ) .