Fill the kettle with a solution of 18 oz (0.5L) white vinegar and 42 oz (1.2L) water and leave to activate for over 1 hour.  2. Empty the vinegar solution from the kettle. Wipe off any mineral deposits with a damp cloth. 3. Fill the kettle with clean water, bring it to a boil, and then discard the water. Repeat before using again. 4. Repeat the procedure if there is still some limescale left within the kettle.