19 C.F.R. § 148.110
The provisions of this subpart are applicable to articles not accompanying a person, including a crewmember, which are purchased in and shipped from American Samoa, Guam, the Commonwealth of the Northern Mariana Islands, or the Virgin Islands of the United States. However, this subpart is not applicable to the importation of unaccompanied articles in a manner prohibited by law or regulation (e.g., mail shipments of alcoholic beverages or alcoholic beverages shipped other than by mail in excess of quantities authorized by State laws or regulations).
The following is a summary of the procedure to be followed to obtain the benefits of this subpart: A person purchasing articles in American Samoa, Guam, the Commonwealth of the Northern Mariana Islands, or the Virgin Islands of the United States would receive a sales slip, invoice, or other evidence of purchase which he would present to the Customs officer along with his baggage declaration, Customs Form 6059-B, and a Declaration of Unaccompanied Articles, Customs Form 255. The latter form is prepared in triplicate for each shipment to follow. The Customs officer would verify the information, indicate on the form whether the article or articles were free of duty, dutiable at the flat rate, or a combination of the foregoing, and validate the form. Two copies would be returned to the traveler, who would send one form to the vendor. Upon receipt of the form the vendor would place it in an envelope, affix it to the outside of the package, clearly mark the package "Unaccompanied Tourist Shipment," and send the package to the traveler, generally via mail, although it could be sent by other means. If sent through the mail, the package would be examined by Customs and forwarded to the Postal Service for delivery. Any duties due would be collected by the mailman. If the shipment arrives other than through the mail, the traveler would be notified by the carrier when the article arrives. Entry would be made by the carrier or the traveler at the customhouse. Any duties due would be collected at that time.
19 C.F.R. §148.110