Can anyone explain the process used for preparing trophies/animal parts for shipment to the U.S.

Chemicals used, facilities where it's done, how it is received, cleared through U.S. Customs, and the U.S. laws covering this.

There's an invasive species bill winding it's way through Congress, the Nonnative Wildlife Invasion Prevention Act (HR 669), that is of concern. Particularly in relation to interstate transport of game or furbearers taken by hunters and trappers.

I would contact any Coppersmith office. They will know.