I have two Spotmatics that I haven't used in a while. A couple of years back I have to put everything in storage in a hurry so these two camera went into storage with film in it. I open one up today to replace the film and notices that the film (Ilford SFX 200) had caused corrosion on the film rails, the corrosion is noticably raised. From what I understadn this will cause focus problem if I use brighter lens such as the 1.4/50mm. And should not be used at all. Given that replacemant value for spotmatics are about US30, shall I attempt self repair of should I just consign these two as parts camera? Also are there any hints on how to prevent this from happening again? I am thinging a thin layer of silicone grease on the film rails once in a while.