Red Devil Lye, also known as Lewis Red Devil Lye Drain Opener, was the trade name for a drain cleaner product sold by the manufacturer Reckitt-Benckiser. The product has been pulled from the market and is no longer available. Similar drain-cleaning products are now sold as Red Devil Lye replacements.
The primary use of Red Devil Lye was as a drain cleaner. The product reacted with grease to form a kind of soap that would dissolve in water and wash away. The caustic product also decomposed proteins in substances, such as hair. The process of mixing the solid product with water also generated heat, which assisted the drain cleaning action.
Red Devil Lye consisted of pure sodium hydroxide. Although marketed as a drain cleaner, it was used by many home soap makers as an ingredient for lye-based soap. Soap is created by mixing fats with lye, in a chemical process known as saponification. Many soap recipes called for the use of this specific product. As lye soap cannot be made without lye, crafters need this product (or an equivalent product) for their soap recipes.
Besides cleaning drains and making soap, lye is also used in the process of making biodiesel fuel from fats. Lye is used to chemically peel fruits and vegetables, to soften olives and to glaze German lye rolls before baking. Hominy is made by soaking dried corn kernels in lye solution. The Scandinavian dish lutefisk ("lye fish") is created using lye.
Sodium hydroxide is also a key ingredient in the manufacture of methamphetamines. Since Red Devil Lye was readily available, this product was frequently used by illegal "meth" labs to produce illicit drugs. The possession of large amounts of the product was a potential sign of this illegal activity. This fact, along with the hazardous nature of the product, may have contributed to the decision to take the product off of the market.
Red Devil Lye (and any substitute product) is a hazardous chemical substance. Sodium hydroxide is extremely caustic and can burn skin and eyes. Also, since the product generates a considerable amount of heat when dissolved in water, there is a risk that the caustic mixture can boil and splatter out of a clogged pipe. Wear protective equipment, such as safety glasses and gloves, when handling the product or a solution made with the product.