Each year the U.S. produces hundreds of millions of tons of metal scrap. A Vanderbilt University research team used scraps of steel and brass - two of the most commonly discarded materials - to create the world’s first steel-brass battery that can store energy at levels comparable to lead-acid batteries, while charging and discharging at rates comparable to ultra-fast charging supercapacitors. The team basically combined scrap metal, laundry soap, and a glass jar. The secret was anodization, a common chemical treatment used to give aluminum a durable and decorative finish. When scraps of steel and brass are anodized using a common household chemical and residential electrical current, the team found that the metal surfaces are restructured into nanometer-sized networks of metal oxide that can store and release energy when reacting with a water-based liquid electrolyte. Unlike some exploding lithium-ion cell phone batteries, the steel-brass batteries use non-flammable water electrolytes that contain potassium hydroxide, an inexpensive salt used in laundry detergent.