I took ideas from a couple of recipes and made my own. This would be good for any scrubbing surface, yet avoids all the nasty chemicals in store bought cleansers (Comet makes me sick!) Scrub gently on porcelain, if you choose to use it on that. Use the eggshells that you have left over from making eggs. Boil them for a few minutes, then dry in the oven on low (250) for a few minutes. Then grind in a coffee grinder or food processor.