Cream of tartar is also known as Potassium bitartrate, and potassium hydrogen tartrate. Cream of tartar is a common ingredient in bath and body products that are in solid form because it helps to harden and firm up products like bath bombs and solid bubble bath products.   It is a bi-product of wine making.  It  makes a great cleanser for household use when mixed with water, and even more powerful when mixed with an acidic liquid such as lemon juice or vinegar.