Hard water deposits on a kettle usually present themselves as white, flaky deposits. These deposits stem from minerals in the water. Some of the more common minerals that cause deposits include magnesium and calcium. Luckily, you can remove hard water stains and return the shine to your kettle quite easily. You don't have to spend a lot of money on harsh chemical cleaners. Use simple, inexpensive items that you may already have at home.
Pour white vinegar into a spray bottle.
Spray the vinegar onto the outside of the kettle and wipe off the stains with a clean, soft rag.
Fill the kettle with a mixture of one part water and one part vinegar.
Bring the mixture to a boil.
Swish the liquid around and pour it out to remove hard water deposits from inside the kettle. If you can still see any hard water stains inside, repeat steps three, four and five.