I think it depends on the scanner. Many newer scanners, like the OpticBook and newer Epsons and Canons, aren't really glass. They're Plexiglas, and it's porous. Those scanners shouldn't be cleaned with any liquid because the moisture will get trapped inside the Plexiglas and will create little bubbles that will distort your scans. This is true of modern laptop screens, monitors, and TVs too. These scanners' instruction manuals say to clean them by wiping the scanning area with a soft, static-free, lint-free cloth. You can either buy these at a computer store, or you can make your own from an old pair of cotton underwear or an old, white cotton T-shirt. Monica Willyard "The best way to predict the future is to create it." -- Peter Drucker