Review on Lenicany 6-Pack Pumice Stone Stick for Toilet Bowl Cleaning - Powerful Cleaner for Hard Water Rings, Calcium Buildup, Stains - Ideal for Toilet, Bathtubs, Kitchen Sink, Grill by Chantel Dickinson

I have very hard water and these limescale stains have been around for years. After 2 pumice stones and about an hour and 10 minutes of cleaning, the toilet is already looking much better. Where the water is leaking, there are still stubborn spots that don't seem to be moving. But I hope that in the end the stones will pull out all the stains. This is the only remedy that has ever made a dent in these spots, so I would recommend trying it. Just be prepared to rub for hours if the calcium buildup is really bad.