Abstract: Predetermined desired areas of solvent-insoluble parylene coatings are removed from substrates made of materials such as plastics, metals, composites, or ceramics by contacting the areas to be removed with a substance that causes the parylene coating to loosen from the substrate sufficiently to permit physical removal, as by peeling or scraping. The substance used is tetrahydrofuran alone, or in combination with a carrier that does not react with the tetrahydrofuran, the parylene, or the substrate, and that makes the mixture sufficiently viscous for application to desired coating areas without affecting other areas contiguous thereto.