How do you clean an icon such as Michelangelo’s David? Carefully, of course. But it turns out that the restorer hired to do the job was maybe too careful. When her bosses insisted on a more invasive cleaning process, she quit. “I hated to do that, because the David is the best job a restorer could have. But I simply could not be party to diminishing Michelangelo’s masterpiece.” Will the alternative method destroy David? “Unlikely. Short of taking a hammer to it like Piero Cannata, or blowing it up, it is, as Ms Parronchi insists, pretty hard to do that.”