39 CFR 263.2 - Policy.
It is the policy of the U.S. Postal Service to establish and maintain schedules specifying the retention periods required for all official and duplicate record copies. Furthermore, it is the policy that all duplicate record copies and non-record material will be disposed of as soon as they have served their purpose.
Title 39 published on 2013-07-01
no entries appear in the Federal Register after this date.