Clean your diffuser routinely. We clean ours once a week. Or whenever we drastically change the scent - like from Raven to Stress Away.
Dump any remaining water and use a cotton ball with rubbing alcohol to wipe out the inside. Use alcohol on a cotton swab to clean the metal sensor. Soap and water won’t remove oils reside. That little sensor is important and will last longer if cleaned!
Never immerse your diffuser to clean it!!
Here are two of my favorite diffuser combos: