Most people who say their ultrasonic skin scrubber does nothing are using it on dry skin. The device runs on water. Sound waves at 30,000 vibrations a second turn the film of water on your face into a fine mist that flushes softened gunk out of pores, and with no water there is no mist, just a metal spatula rubbing your cheek. Keep your face properly wet and the same device suddenly earns its place in the routine.