I usually use the spray wax (Mothers, Turtle Wax) on my wheels, door edges, door jams and the inner under the hood area/radiator support etc.
Today I had the bright idea to spray inside the wheel wells in hopes of offering the frame, wheel wells and underside some extra protection against the overuse of salt here in RI.
What do you think? Good idea? Bad idea? Or maybe just a waste of wax?

Spray!

Usually when I wash my car i'll spray armorall protectant in the wheel wells, gives it a nice glossy black look and i would imagine protects it a bit