19 CFR § 12.126 - Notice of abandonment.

If the importer intends to abandon the shipment after receiving notice of refusal of entry, the importer must present a notice of intent to abandon in writing to the port director or electronically to ACE or any other CBP-authorized EDI system. Notification under this section is a waiver of any right to export the merchandise. The importer will remain liable for any expense incurred in the storage and/or disposal of abandoned merchandise.

[CBP Dec. 16-28, 81 FR 94986, Dec. 27, 2016]