Armor All Fresh Fx Tranquil Skies Duct and Vent Cleaner Odor Neutralizer is designed for auto ventilation systems. This odor eliminator formula treats vents, ductwork, evaporator core and drain pan area to eliminate odors. Armor All duct cleaner also removes dirt that resides in ductwork. This auto cleaner for vents is easy to use. Simply spray this car interior cleaner into each vent and into the outside air intake grille, turn on the air conditioner, and let ventilate. The resulting car scent combines notes of apple, freesia and lush greens. Help keep your car smelling fresh with Armor All.