After the package is sealed, VCI fills the enclosed space, VCI molecules settle on all the metal surfaces and dissolve to form a thin layer. This process starts as soon as the package is closed and ends within a few hours.
As soon as the space is saturated with VCI vapors the process stops. After the package is opened the VCI material inside the film will evaporate and refill the space.
The VCI packaging performs even if the space is not fully sealed.