The flag should be cleaned and mended when necessary.
When a flag is so worn it is no longer fit to serve as a symbol of our country, it should be destroyed by burning in a dignified manner.
Note: Most American Legion Posts regularly conduct a dignified flag burning ceremony, often on Flag Day, June 14th. Many Cub Scout Packs, Boy Scout Troops, and Girl Scout Troops retire flags regularly as well. Contact your local American Legion Hall or Scout Troop to inquire about the availability of this service.
http://www.usflag.org/flagetiquette.html
