Related Clues:

• Neon or Freon
• Ether
• Fuel for some 12-Downs
• Methane or butane
• Fun time, in slang
• It's crude, then refined
• Petrol (US)
• Word with tear or laughing
• Reversed slump in American petrol
• Purchase from a pump
• Talk about fuel
• Airy matter
• Reversal of decline in fossil fuel
• Number for a surgeon?
• Radon, e.g