I would try Fray Check. I might try it on a less visible location first. We used in a lot in the Marine Corps (tents, uniforms, etc). Sounds funny that a Marine knows about the best sewing supplies, lol, but we are a resourceful group! It dries clear and not shiny.
http://www.amazon.com/Dritz-1674-Liquid-Sealant-0-75-Ounce/dp/B000YQKIDY
http://www.amazon.com/Dritz-1674-Liquid-Sealant-0-75-Ounce/dp/B000YQKIDY