Yes you can use the diffusing function alone by switching off the lamp separately.
To clean the surface of the white glass aromatherapy diffuser, wipe with a clean, damp, soft cloth as often as needed. We recommend wiping the reservoir with a clean, damp, soft cloth at least once every 2 weeks. Depending on your usage, and the amount of essential oils used, you may want to clean the reservoir and ultrasonic membrane more frequently for best performance. For the most thorough clean, pour a 50/50 mixture of vinegar and water into the reservoir, then soak for 5 minutes. Brush reservoir walls, base, and ultrasonic membrane clean with a soft bristle brush and rinse. Never tough the membrane with your fingers because the natural oils on your skin can damage the membrane. Clean the membrane once every couple of weeks. Clean and dry the unit completely before extended periods of inactivity.