How to clean the candle in the cup?

Update:24-07-2018
Summary:

When the freshly boiled water goes in, the candle begin […]

When the freshly boiled water goes in, the candle begins to soften when the temperature reaches 40 degrees Celsius, and becomes liquid at about 70 degrees Celsius.
Then pour out the boiling water in the cup, and the candle turned into a liquid comes out with the boiling water.
A few more times, the water cannon cups cleared the candle and killed the bacteria.