It was easy. I finally got some vinegar and filled it up and let the kettle sit overnight. Rinsed it and gave it a wipe with a wad of paper towel and the scale and residue from the scale is all gone.
Shoulda done it earlier. The wasted psychic energy, every time I peered in and saw the scale…
I learned the word lime scale today.
Scale… Someone in the past must have thought, let’s just use one word for all the meanings. (You have to save wherever possible.): Scale in the cambridge dictionary