Some forms of corrosion are known to be caused by bacteria (the rusting of the Titanic, for example.) What if *ALL* metallic corrosion turns out to be biological rather than from simple chemistry? In that case, tailored antibacterials could at long last "cure" all unwanted rust (cured in the medical sense). Probably a cocktail of drugs would be needed for the various iron-eating flora, and different drugs would go after the aluminum-eaters, etc.