Related Clues:

• Deposit in chimney
• Something stuck down the chimney? Santa out of training for starters!
• European city that's less urban, somewhat regressive
• Union's base turned smaller during brief skirmish
• Not so much returned in sweep, as hospital's lost capital
• Chimney substance
• A pollutant
• Chimney pollutant
• 29-Down buildup
• Seat of the European Commission
• Film in a flue
• Laundry woe at the Claus home?
• Dirty coat in a chimney
• Flue grime
• Air polluter