US punk rockers Green Day have been hailed for saving the life of a 12-year-old British girl from a live World War II grenade. The AMERICAN IDIOT hitmakers sport a picture of a grenade on the single's promotional T-shirt, and helped fan RUBY WILSON from Halifax identify the mysterious metal object in her garden on Sunday (11JUN06) as an explosive. A bomb disposal unit was dispatched and blew up the device in a controlled explosion.