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.
You may see some pumice stones that have broken off due to erosion by the sea. Amazingly, they will actually float on the water for some time. Dense stones, of course, do not float on water. But because pumice is full of air bubbles, it is less dense than water.