Possible Clues:

• Guitar string clamp
• Movable bridge
• Godfather chopping tail off fowl
• Sonny Corleone, for one
• Hat on old Mafia boss
• Don's partner in the underworld
• Mafia leader's way of raising the tone?
• Guitarist's key-changing tool
• Headgear given to Oscar for playing bridge?
• The "C" in the musical instruction "D.C. al fine"