19 CFR § 191.74
Exportation by mail
July 16, 2020
If the merchandise on which drawback is to be claimed is exported by mail or parcel post, the official postal records (original or copies) which describe the mail shipment shall be sufficient to prove exportation. The postal record shall be identified on the drawback entry, and shall be retained by the claimant and submitted as part of the drawback claim (see §191.51(a)).
[T.D. 98-16, 63 FR 11006, Mar. 5, 1998; 63 FR 15289, Mar. 31, 1998, as amended by CBP Dec. 15-11, 80 FR 47407, Aug. 7, 2015]