I recently bought a 1970 2D Ford Maverick. The exterior was in great shape. But the interior needed some work. That's what brought me here. The rear interior quarter panels have started to crumble and crack. I could use some tips on how to handle this. I've been looking on trying to find replacements but it seems almost impossible. Is there anyway I can repair it and make it look good? This is something that will be visible. It is crumbling at the top near where the small window would be. Any help is appreciated. Thanks!