In general, we do not recommend using detergent. Although it sounds cleaner, there may be detergent remaining, which may be bad for our body when we swallow.
We would recommend the below way to clean.
Simple way --- boil water for once or twice with the electric boiler
For electric boiler of 3.0L or above, you may boiler one pot of water with 1 bag of citric acid (30g)*. Rest it for 6 hours after boiled, and then pour away. If you find any odors after cleaning, you may boil the water for one or two times additionally. Electric boiler with less than 3.0L, you may adjust the portion of citric acid proportionally.
*There are a variety of citric acid with different acidity in the market. We would recommend using our citric acid (made in Japan) to avoid acidic corrosion.