I need to replace the mesh in some window screens of my new place. However, these screens seem to be permanent or at least unlike others I have encountered. There are no visible pins, tabs, springs, etc. They can't be removed from the outside because of an encasement. There are what appear to be tabs at the top but I can't pull the screens out. The brand is Apollo 94-2. Anyone have any ideas of how these come out, it they do? Thanks.