18 U.S.C. § 1762: Marking packages

All packages containing any goods, wares, or merchandise manufactured, produced, or mined wholly or in part by convicts or prisoners, except convicts or prisoners on parole or probation, or in any penal or reformatory institution, when shipped or transported in interstate or foreign commerce shall be plainly and clearly marked, so that the name and address of the shipper, the name and address of the consignee, the nature of the contents, and the name and location of the penal or reformatory institution where produced wholly or in part may be readily ascertained on an inspection of the outside of such package. Whoever violates this section shall be fined under this title, and any goods, wares, or merchandise transported in violation of this section or section 1761 of this title shall be forfeited to the United States, and may be seized and condemned by like proceedings as those provided by law for the seizure and forfeiture of property imported into the United States contrary to law.