19 CFR § 158.45 - Exportation of merchandise.
(a) From continuous Customs custody. Merchandise in Customs custody for which entry has not been completed and merchandise which has remained in continuous Customs custody that is covered by a liquidated or unliquidated consumption entry may be exported under Customs supervision in accordance with §§ 18.25 through 18.27 of this chapter, with refund of any duties that have been paid.
(b) After release from Customs custody. Except as provided for in paragraphs (c) and (d) of this section, no refund or other allowance in duties shall be made because of the exportation of merchandise after its release from Customs custody unless a drawback of duties is expressly provided for by law (see part 191 of this chapter).
(c) Prohibited merchandise. If merchandise has been regularly entered or withdrawn for consumption in good faith and is thereafter found to be prohibited entry under any law of the United States, it may be exported under Customs supervision in accordance with §§ 18.25 through 18.27 of this chapter, with refund of any duties that have been paid. In lieu of exportation, the merchandise may be destroyed in accordance with § 158.41.
(d) Not legally marked merchandise. When merchandise found to be not legally marked is exported or destroyed under Customs supervision after once having been released from Customs custody, as provided for in section 304(f), Tariff Act of 1930, as amended (19 U.S.C. 1304(f)), such exportation or destruction shall not exempt such merchandise from the payment of duties other than the marking duties.