Related Clues:

• It's left on the table
• Subject of an anonymous call, maybe
• Service bonus
• Bit of help
• Capsize
• Part of an iceberg that's visible
• Helpful suggestion
• Wait for it
• Leave cash
• Pointed extremity
• You leave it behind in a restaurant
• Iceberg feature, figuratively
• Redcap's reward
• 15%, often
• Reward for service