Possible Clues:

• Brown, possibly dark, mug
• Mug takes tracked vehicle on a road
• Drank a rum, after time, leaving beer mug
• Mug-like drinking vessel
• Dark tan brew may go into it
• Metal beer mug
• A mug for beer
• Beer-glass
• It starts to get brown before it can be made dark for the drinker
• Time and capital endlessly used on duke's vessel