Many performers use "homemade" formulas. Almost every solution, made at home with the help of household detergents, is the subject to fermentation and souring if the dirt gets into it (such as your skin, dust from the props, leaves, hair). It happens, because in the solution there is a lack of preservatives and other substances, that can help to maintain the initial qualities. As the result, a lot of such products spoils and is disposed.