Professional Series PS77692 Manual Del Usuario página 4

When dry boil happens, first pull out the plug, then fill the kettle. Do not use
the kettle again until it cools down.
Never immerse the kettle and the base unit into water. First pull out the
plug, then the kettle can be cleaned with a damp cloth. Do not wash
the kettle with sharp or rough stuff.
After using for a certain time, a build-up of limestone may occur inside the
kettle, reducing the performance of the kettle and the heating element.
Use the solution of vinegar ad water for clean-up.