We have well water with a Kinetico water softener, but still get stubborn ring stains periodically. I had tried numerous cleaners, CLR, vinegar + baking soda, and more with no luck. The only thing that removed the mineral deposit ring was manually scraping it with a razor blade -- not fun.This pumice stone was super easy to use and got rid of the ring with just a few minutes of scrubbing. YAYYYYYY! I immediayely proceeded to scrub all 3 toilets in our house using only about 10% of one stick. A perfectly white toilet is oddly satisfying. LOL.I've used pumice stones for sweaters (removes pilling) and feet (removes calluses), so I was already familiar with the semi-fragile nature and subtle sulfer smell.TIPS:- It works best NOT submerged. (Submerging will weaken and disintegrate the pumice faster.) Before using, lower the toilet water level by pushing a toilet scrubber deep into the hole about 10 times. That should expose the ring sufficiently for easy scrubbing.- DON'T force it. Pumice is a gentle stone and doesn't require arm power to work well. Find the flattest angle and then gently rub a few times. The pumice dust actually sticks to the raised mineral deposits after a few scrubs, so you can see where to scrub more. If chunks break off or you use more than 10% of a stick on 1 toilet, you're applying too much pressure or need to choose your angle more wisely.After using, I lightly rinsed the pumice, patted dry with paper towel, and placed the stone end in a ziploc bag. Then I stuffed it back in the original box packaging for easy under-sink storage.I wish I had this product a long time ago; it's a game-changer and such a relief that I don't have to look at nasty toilet rings anymore. Highly recommend!