Pilot reported salt had been used as a ramp surface deicer at AVL and noticed that the salt had contaminated the reporter's aircraft.

Narrative

We had a planned departure this morning. As I walked on the ramp; I took note of the salt that was used as a deicer on the pavement. Typically; this practice is discouraged since it is possible to track salt into an aircraft. Both myself and another pilot commented we had not come across something like this in several years.We soon after arrived at the aircraft and noticed the aircraft was parked in an area that was heavily salted. White salt powder and large salt crystals covered an area approximately 150 feet x 100 feet. With over decades of experience at a midwestern airport; I am well versed in airport snow removal and I am aware that salt should never; ever be used at an airport due to the corrosive properties. I witnessed Aircraft Y park next to our aircraft in the salt area and noticed white salt dust being disturbed by the propellers just prior to aircraft engine shut down; basically contaminating the aircraft.Upon our return to our home base; our maintenance personnel recommended a complete aircraft exterior wash along with an engine wash. Maintenance personnel also discovered dozens upon dozens of salt crystals on the aircraft entry steps; in the pilot area; and in the passenger cabin flooring.