Volatile corrosion inhibitors (VCI) Paper, on the other hand, operate a bit differently. They are used to provide corrosion protection to metal components in enclosed areas during long-term storage or shipping. The corrosion inhibiting compounds coated on the VCI packaging material (paper, plastic or foam) are dispersed in vapor form (volatilized) into the surrounding atmosphere. The VCI molecules migrate from the coated media directly to the surface of the metal to form a thin molecular layer of protection. Because VCIs depend on the diffusion of chemicals into the air, they are most effectively used in enclosed environments with limited air circulation.