The Ultrasonic Jewellery Cleaner can simply be used with clean lukewarm or room-temperature water. Pour the water into the chamber using a cup and fill the it up to the limit standard line (labelled MAX).
If deep cleaning is required, add a pea-sized amount of mild, unscented soap. Avoid any harsh chemicals such as dishwashing liquid, washing detergent, chlorine, bleach, or other household cleaners.