One of the many things Star Wars innovated was the look of an old/used/dirty version of space. Over the years I have come up with a few ways to weather a prop or make it look old and used.

Light weathering

• Slight distressing of the metal, and use of dark colour in the crack and grooves

Medium weathering

• Distressing the metal
• sanding off exposed metal under the paint, coating, or anodizing
• Dark colour in the cracks and grooves

Heavy weathering

• Distressing of exposed metal
• nicks and damage
• sanding off exposed metal under the paint, coating, or anodizing
• Dark colour in the cracks and grooves

Faux aging

• Special chemical treatment of the metal to make it appear older and darker
• abrasion to bring out the metal edges
• Works best in combination with heavy weathering above