The washboard is mounted in a wooden frame while the frottoir is made only from the metal ribbing and is hung around the neck and called the Cajun Rub-Board Vest.
The frottoir or vest frottoir (from Cajun French "vest to be rubbed") is played as a stroked percussion instrument, often in a band with a drummer, while the washboard generally is a replacement for drums.
In a jug band, the washboard was stroked with a single whisk-broom and functions as the drums for the band, playing only on the back-beat, for most songs, as a substitute for a snare drum. In a four-beat measure, the washboard will stroke on the 2-beat and the 4-beat. Best sound is achieved using a single steel-wire snare-brush, or whisk-broom.
However, in a jazz setting, the washboard can also be played with thimbles on all fingers, tapping out much more complex rhythms, as in the Washboard Rhythm Kings, a full-sized band.
Some washboard players may add other small percussion devices to the washboard, such as a cymbal, woodblock, or cow bell, which can periodically be struck to vary the effect.
A frottoir is played with a stroking instrument (usually thimble-gloves or a pair of bottle-openers) in each hand. In a 4-beat measure, the Frottoir will be stroked 8 to 16 times. It plays more like a Latin percussion instrument, rather than as a drum.