Possible Clues:

• Epitome of deadness
• Symbol of deadness
• Proverbially, no longer a stud
• Boss, supposedly dead cross after returning to nick
• As dead as a —
• Dead as a ...-very dead indeed
• For openers, fixer is popularly believed dead
• Large-headed fastener
• Stud proverbially dead
• Old iron — a material that's dead