Drones? Lasers? Study offers cleaning ideas for Gateway Arch
newsdepo.com
ST. LOUIS (AP) - The Gateway Arch gradually is losing some of its silver sheen, as a variety of forces - from salt to body oils to graffiti - take a toll on the stainless steel monument to westward expansion and a symbol of St. Louis. Now, a group of ...Drones? Lasers? Study offers cleaning ideas for Gateway Arch
ST. LOUIS (AP) - The Gateway Arch gradually is losing some of its silver sheen, as a variety of forces - from salt to body oils to graffiti - take a toll on the stainless steel monument to westward expansion and a symbol of St. Louis. Now, a group of ... Read more