First-Class Package International Service items bearing a computer-generated customs form with customs data that has been electronically transmitted (e.g., using Click-N-Ship service, an authorized PC Postage vendor, or the USPS Web Tools system) may be deposited through any of the following methods, provided postage is paid by a means other than the use of postage stamps:
Customers must present the following First-Class Package International Service items requiring a customs form to an employee at a Post Office retail service counter. Deposit and pickup methods listed in 255.11 are prohibited. The Postal Service will return improperly presented items to the sender for proper entry and acceptance.