19 C.F.R. § 151.66
Duty shall be assessed and collected on samples taken pursuant to any provision in this subpart, whether taken by the importer or by Customs, unless an exemption or remission is obtained by compliance with an applicable provision of the law or regulations. The duty shall be assessed upon the samples in accordance with their condition at the time of importation, except in the case of merchandise manipulated in warehouse pursuant to section 562, Tariff Act of 1930, as amended (19 U.S.C. 1562 ) . The collection of duty on the samples may be postponed when the importation concerned is not entered for consumption until the withdrawal of the merchandise from which the samples are taken, or until an application for the destruction or abandonment of such merchandise has been accepted pursuant to an appropriate provision of the law or regulations.
19 C.F.R. §151.66