19 CFR § 10.138 - Proof of use.

---
identifier: "/us/cfr/t19/s10.138"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "19 CFR § 10.138 - Proof of use."
title_number: 19
title_name: "Customs Duties"
section_number: "10.138"
section_name: "Proof of use."
chapter_name: "U.S. CUSTOMS AND BORDER PROTECTION, DEPARTMENT OF HOMELAND SECURITY; DEPARTMENT OF THE TREASURY"
part_number: "10"
part_name: "ARTICLES CONDITIONALLY FREE, SUBJECT TO A REDUCED RATE, ETC."
positive_law: false
currency: "2026-04-05"
last_updated: "2026-04-05"
format_version: "1.1.0"
generator: "[email protected]"
authority: "19 U.S.C. 66, 1202 (General Note 3(i), Harmonized Tariff Schedule of the United States (HTSUS)), 1321, 1481, 1484, 1498, 1508, 1623, 1624, 4513."
regulatory_source: "28 FR 14663, Dec. 31, 1963, unless otherwise noted."
cfr_part: "10"
---


# 10.138 Proof of use.

Within 3 years from the date of entry or withdrawal from warehouse for consumption, the importer shall submit in duplicate in support of his claim for free entry or for a reduced rate of duty a certificate executed by (1) the superintendent or manager of the manufacturing plant, or (2) the individual end-user or other person having knowledge of the actual use of the imported article. The certificate shall include a description of the processing in sufficient detail to show that the use contemplated by the law has actually taken place. A blanket certificate covering all purchases of a given type of merchandise from a particular importer during a given period, or all such purchases with specified exceptions, may be accepted for this purpose, provided the importer shall furnish a statement showing in detail, in such manner as to be readily identified with each entry, the merchandise which he sold to such manufacturer or end-user during such period.

[T.D. 71-139, 36 FR 10727, June 2, 1971]