... , Walkman , to get extremly and thorough washing. 2.Glasses, optical instrument: After ultrasonic washing,all the things of the world obvious clearly ... rid of a pesticide while washing .Besides ,if you long-time to put use of ultrasonic to protect skin ,your ... all the problems.5.Clock and watch , precision instrument: Have ultrasonic cleaner ,you shouldnt Dismount screw , gear wheel , hairspring spring ...