I doubt this happens to many people. Old pair of diadora SPD shoes, started to hear jangling metal noise when I rode and walked. Checked shoe and the floating plate that takes the SPD cleat had cracked in half. Tried krazy glue, didn't work. Thought about somehow removing the offending piece of cracked plate -- no dice, would have to destroy the shoe.
Then I realized I only needed the top cleat position, all the way forward. So I cut off a piece of old inner tube and jammed it in between the two pieces of cleat plate. No more annoying rattle.