"Unmanifested material" is any material that you ship without a manifest (an official list of the cargo that is being shipped.)

What does unmanifested package mean?

Unmanifested parcels are parcels that are scanned by the Postal Service but not included on the mailer's manifest.

What is unmanifested goods?

Unmanifested cargo, or smuggling, can include the unlawful introduction of drugs, weapons, or humans into a shipment. ... Criminals are continuously evolving and becoming more creative in using legal shipments to smuggle their illegal cargo.