Many readers may remember a cleaning product called Boraxo, in a shaker can.
Well, you can make your own. Buy Borax in the big cardboard box in the laundry section, and mix 1 part Borax to 4 parts baking soda in a shaker can.
I love Bon Ami cleaning products, but for some tasks, this is even better. Stains on porcelain will come out if you wet the surface, sprinkle this on, let it set for a few hours and then wipe clean.