The dust that spreads from a ginger person's head normally in strong winds or through scratching of the scalp. Be careful, rust dust is very contangious. If the small particles that constitute a ginger man's head spread on to another human it will instantly turn them ginger too. Also known as the ginger disease.
John stop spreading your filthy rustdust around, you'll infect us all!
Term used at auto dealerships to describe supplemental "paint protection" and rustproofing that is sold during the part of the sale where the financing is arranged. It is a source of "back end" profit for the dealer.
"That customer was a total lay-down; he bought Slip & Trip (disability insurance), Choke & Croak (life insurance) and Rust & Dust"