Merchandise regularly entered or withdrawn for consumption in good faith and denied admission into the United States by any Government agency after its release from Customs custody, pursuant to a law or regulation in force on the date of entry or withdrawal for consumption, may be destroyed under Government supervision. In such case, the destroyed merchandise is exempt from duty and any duties collected thereon shall be refunded. In lieu of destruction, the merchandise may be exported under Customs supervision in accordance with Sec. 158.45(c). (Sec. 558(a), 46 Stat. 744, as amended; 19 U.S.C. 1558(a))