Recently I noticed something like dirt - or corrosion? - on one of the rollers. I included a photo, but it's hard to photograph something so small. Due to current circumstances, I cannot send a camera out for repair .. so I'm wondering if this is do-able at home. Is it possible to get the rollers separated and clean them? Or is there a chance of screwing-up the film-thickness-sensing-mechanism (in which case I'll leave it be.)