Possible Clues:

• Vessel reportedly named after a US president
• Old woman lacking energy to hold old Scottish pot
• Contents of a cold urn poured out into kettle
• A pot named Ronald, by the sound of it
• Witch's brewing pot
• Large deep pot for boiling things in
• Sounds as if one summoned Ronald to be on fire
• Pot roughly round, roughly litre content
• Ancient, according to Macbeth, witch mostly is seen round this?
• 'Macbeth' prop