Step 6 · Use Pumice Stone for Stubborn Stains

This is the step people usually slow down on. Go finger-tight first, then a quarter turn. No rush — replay the clip whenever it helps.

For any remaining stubborn stains, a pumice scouring stick is the most effective tool. It is critical that you wet both the pumice stick and the porcelain surface before you begin scrubbing. Dip the stick in the remaining vinegar or under a faucet. Gently rub the wet stone directly on the stain using a back-and-forth motion. The abrasive nature of the pumice will grind away the mineral deposit without scratching the porcelain, as long as both surfaces are kept wet.