The spirals of metal left over from machining could become a substrate for the highly efficient catalysis of hydrogen and oxygen evolution reactions, new research finds. These metal shavings, called swarf, provide a textured surface upon which the researchers deposited catalytic metals such as platinum and cobalt. This technology could provide a use for metal scraps that are rarely recycled and produce hydrogen at a lower cost by sparing the amount of platinum catalyst necessary for water-splitting reactions.