What it sounds like, and the records to hear it on.
A washboard is a tool designed for hand washing clothing. With mechanized cleaning of clothing becoming more common by the end of the 20th century, the washboard has become better known for its originally subsidiary use as a musical instrument. The washboard and frottoir (from Cajun French "frotter", to rub) are used as a percussion instrument, employing the ribbed metal surface of the cleaning device as a rhythm instrument. As traditionally used in jazz .