This preparation is used by dentists. Pure muriatic acid one ounce,
water one ounce, honey two ounces, mix thoroughly. Take a tooth-brush,
and wet it freely with this preparation, and briskly rub the black
teeth, and in a moment's time they will be perfectly white; then
immediately wash out the mouth well with water, that the acid may not
act on the enamel of the teeth. This should be done only occasionally.