A method of reducing if not eliminating the possibility of tearing or ripping of a mesh screen of a filter during the manufacturing process includes the step of intentionally deforming the mesh screen. With this technique, as the plastic material that forms the frame of the filter begins to expand or change shape, as a result of the heating and squeezing steps involved with the molding process, the deformed mesh screen will be able to accommodate the relative changes in shape without tearing or ripping of the mesh screen. With the invention, numerous shapes and configurations of tools may be used to provide the intentional deformation of the mesh screen during the manufacturing process as well as to provide for control over the amount and degree of mesh screen deformation. Also, the resulting filter will have a mesh screen that has improved retention capabilities which will enhance the performance of the filter.