Possible Clues:

• One inside conceals a Trojan horse's cover
• Trapping a number cruncher, jailing one
• Outside a capital city study a type of ornamentation
• Rich clothing around Juliet's intended, nothing new
• Horse’s trappings a Trojan prince wrapped in fleece?
• Ornamental covering over a horse's saddle or harness
• Fine covering swindle involving key capital
• Saddle decorator over chasing source of plaster in tin
• Deception about a Trojan Horse's cover
• Swindle over a capital cover for horse