This is particularly for a 240mm Rodenstock S, there is some dust between the lens elements. It's unlikely to effect the image however I do have a lens wrench to pull apart the elements to blow them out. However I'm unsure if there are any seals, tolerances, gaps or torques that would effect by me unscrewing it. Worth noting this in the inner cells not the sides facing the shutter. Would it be as simple as unscrewing it, blowing it out and just tightings it back down again?