Kilrock K is a mulit-purpose descaling solution that helps removes limescale. Dualit recommends using Kilrock K once a month to descale your kettle and help to prevent a build-up of limescale. If you live in a hard water area, you may need to descale more often. The descale process is simple and takes from 15 minutes to one hour, depending on the build-up of limescale in your kettle.