Possible Clues:

• Pot cover
• Pot warmer
• It covers pot belly fine, ultimately coat's for going out
• Coat? Yes! (anag)
• It keeps pot hot
• Warmer coat? Yes, boiling
• Padded covering to keep a pot of popular beverage warm
• Coat? Yes (anag)
• It keeps the beverage hot
• ETA's coy revolutionary keeps the heat on the Earl perhaps