Related Clues:

• Flue stuff
• Chimney sweep's target
• Sweep's sweepings
• Lampblack, essentially
• Chimney dirt
• Coal dust
• Flue accumulation
• Sweep's collection
• Santa's laundry stains
• Chimney sweep's grime
• Stain on Santa's coat, you'd think
• Lampblack source
• Flue deposit
• Schmutz on Santa
• Flue substance