Common rust, which has the formula Fe2O3.
sea water / baking soda / milk of magnesia / ammonia solution / soapy water / bleach and drain cleaner
Salt, soaps, some cleaning agents, toothpaste and some batteries i think.
Toothpaste contains a minimum amoun of ALKALI to kill the acids off your teeth! Other household items contain alkalisuch as Black coffee and various oven cleaners. Bleach, Bicabonate of Soda, Washing...
washing up liquid food coloring tooth paste