Abstract: The invention describes the use of magnetic platelet particles as a multifunctional additive to various formulations of polyolefin plastic films usable to fabricate packaging and to provide said packaging with similar barrier properties as aluminium metallizations or other gas barriers, with the added benefit of allowing separation and recovery of the packaging by magnetic means. Such novel additives, films and packaging are environmentally friendly and food-safe, so that after use they can be either recovered for reuse, composted, or dumped in the environment to biodegrade. The invention comprises various types of films comprising the additive and methods to improve the properties of said films.