What is cream of tartar? Cream of Tartar is potassium bitartrate. It is an acidic salt that comes from grapes and it is made from the crystals that form on the inside of fermentation tanks while making wine. This is purified and used for baking and cooking, but as I just found out recently, it is great for cleaning too.
You mix a few tablespoons of this with a little hot water and it cleans the following items really well:
Copper kettles become clean when you mix cream of tartar with lemon juice and rub the copper part of the kettle with it. Porcelain is no match for cream of tartar when cleaning needs to be done.
It makes a good soft abrasive cleanser.
You can find it in the spice area of your local grocery store. Cream of tartar will clump if left out in a humid environment. Store in a cool, and very dry place.
By Robyn 
Baking soda will do the same thing and is considerably cheaper.