How do I clean the ultrasonic membrane without damaging it?

Clean the transducer/ultrasonic membrane with a 50/50 mix of white vinegar and water on a cotton swab. Wipe off with a damp cotton swab. Never touch the transducer/ultrasonic membrane with your fingers as the natural oils in the skin can damage the surface. Never submerge the base in water or any other liquid, and never use detergent or scrape it with a hard object.