The 2450 holds film in mid-air. It's not in contact with anything. If your smudges, dust, whatever are in focus then before disassembling anything, better figure out how they can be in focus. They are all most likely on the transparency itself. Is it just a matter of expecting cleanliness that is unavailable? Scanning always leads to endless retouching of dust, etc. It's just a fact of life, and a major factor for people's enthusiasm when they first try a digital camera. Good luck but I suggest no big rush to disassembly...