Possible Clues:

• Alternative to denim
• Kathleen Henry finds half the characters from 24 across in shade
• Colour of driver's accessory, as you might say?
• Dull uniform color
• Army uniform
• Dull colour is something motorists want to go, some say?
• Material used in making sheikh a kilt
• Park-ranger garb material, often
• Colour of military uniforms
• Uniform colour of Gurkha kit