Ans - How to Clean a Rice Cooker Fill the rice cooker with water and add a teaspoon of washing-up liquid. Turn the cooker on. Once the water has boiled, turn it off and leave it to cool down. Empty the water and rinse the rice cooker with fresh water. Fill the rice cooker with water and wash up liquid. Turn the cooker on. Once the water has boiled, turn it off and leave it to cool down. Empty the water and rinse the rice cooker with fresh water