Federal law stipulates many aspects of flag etiquette. The section of law dealing with American Flag etiquette is generally referred to as the Flag Code. Some general guidelines from the Flag Code answer many of the most common questions:
The flag should not be used for any decoration in general. Bunting of blue, white and red stripes is available for these purposes. The blue stripe of the bunting should be on the top.
The flag should never be used for any advertising purpose. It should not be embroidered, printed or otherwise impressed on such articles as cushions, handkerchiefs, napkins, boxes, or anything intended to be discarded after temporary use. Advertising signs should not be attached to the staff or halyard.
The flag should not be used as part of a costume or athletic uniform, except that a flag patch may be used on the uniform of military personnel, fireman, policeman and members of patriotic organizations.
clipped from: www.usa-flag-site.org 