Abstract: This invention describes a method of masking a workpiece to prevent the adhesion of a deposited tightly adhering conformal coating formed from the condensation of a vaporous diradical such as paraxylylene on selected portions of the workpiece. Specifically the process of the invention requires the covering of the areas of the workpiece, to which adhesion is not desired, with a non-polymerizing hydrocarbon and placing the covered area in close contact with an open cellular material containing a predominance of interconnecting cells which provides a large surface area for condensation of the unwanted condensate of the diradical, exposing the workpiece to the vaporous diradical, removing the workpiece from the open cellular material and immersing the workpiece in a solvent for swelling and dissolving the hydrocarbon covering.