Classified as a scraped idiophone, a musician uses the washboard as a percussion instrument to add a "raspy" or scraping sound to the rhythm of a composition. The performer scrapes the corrugated surface with common finger thimbles (used in sewing). The washboard can provide the normal drum rhythms or can add another layer of rhythmic interest to the composition. The sound is similar to that produced by a güiro. The washboard was originally used when real percussion instruments were not available to amateur performers in poor neighborhoods and rural areas in the United States in the mid to late 19th century. The washboard is still used as a novelty instrument in bluegrass, dixieland, and other folk music traditions. A version the washboard is currently being used in the Zydeco style known as a rub board.
Photos courtesy of Lark In The Morning