By means of Plasmatreats Openair® plasma pretreatment foils and films can be treated both in part and over their entire surfaces. In doing so the mechanical properties of the material remain unchanged. By selectively controlling treatment parameters such as temperature, jet positioning, jet width and speed these thin materials can be efficiently cleaned, activated or coated without the use of additional substances. This can result in significant cost savings and dispense with the use of environmentally harmful processes.