Possible Clues:

• Bull, over time, wearing hide
• Loud and empty talk to lift a balloon?
• What a balloon or showoff is full of
• Empty, boastful talk
• Bloviator's contribution
• Locks to secure old books? That's silly talk!
• Hogwash
• Vapid talk from entertainer with no small appearance
• Balloon type
• Empty talk from the first three characters in 26 across on radio