Possible Clues:

• Empty talk
• Vacuous chatter
• Rubbish religious books in Barnet
• Shock maybe about old books offering nonsense
• Rubbish musical about Heart of Midlothian
• Bluster (informal)
• Gas required before balloon goes up?
• Guff one has to endure in sauna?
• Erotic song that's supposed to impress listeners