-. Pour vinegar of appropriate amount into the kettle.
-. Place the kettle stand under non-heating state for 1 hour.
Using citric acid:
-. Pour water of appropriate amount inside the kettle and boil it.
-. Pour 25g citric acid inside the kettle and place it stand for 15 minutes.
After emptying the kettle, you need to clean it for 5-6 times and repeat it if necessary.
