CLR will do it: https://amzn.to/2OZ7a8F
How to clean limescale with vinegar
We soak our bowl with 2 or more cups of vinegar over night or during the day if everyone is going to be gone. Then the regular bowl brush will remove most of it. I also sometimes have to use Mr. Clean toilet bowl magic scrub on touch stains. The vinegar is cheaper and does allow the scrub brush to remove most if not all mineral stains.
This post is really helpful: https://www.thesuburbanmom.com/2012/01/11/how-to-finally-get-rid-of-the-toilet-bowl-ring/
Spray with WD40 and leave it for about 30 minutes then rub it off.
a pumice stone works well for that.
Thanks. Going to try the WD40
The pumice stone worked magic but I did not have any luck with the WD40