Averages are for Corvallis Municipal, which is 5 miles from Corvallis.
Warnings. Do not use pumice stones to clean marble, laminate, plastic or fiberglass toilets; doing so will result in permanent scratches. A dry pumice stone will also scratch porcelain, so be sure to keep the stone and the toilet surface wet at all times.lean With a Pumice Stone. Before cleaning a porcelain toilet with a pumice stone, you must thoroughly wet both the stone and the surface to be cleaned and keep the stone and the surface wet as you work.
To use the pumice stone, do the following: 1  Wet it with some of the water that is remaining in the toilet bowl after draining the tank. 2  Rub at the stain with gentle and consistent pressure until the stain is gone.  Keep the pumice stone and the bowl wet when cleaning so you don't scratch the porcelain.