Lye is a mixture of sodium perborate, citric acid and Marseille soap. The presence of percarbonate allows Lye to free active oxygen (effective >35°C) with warm water. The Oxygen melts the grime, solubilizes it and removes it naturally. Marseille soap helps detergent action and citric acid removes the lime scale. Does not contain composites of phosphorus , optical brighteners, anti block, by assuring a cheap washing in total respect of the Environment and of people.