I wasn't sure where to ask this question so I figured I would put it here. I have the Nikkor 18-70mm lens. The other day, while I was changing over to it, I noticed how dusty it was. So, I grabbed the old lens cleaning cloth and began cleaning it up. Only problem was, it was on the INSIDE of the lens. Can this be cleaned? Do I have to send it back to Nikon for cleaning or can a reputable shop clean something like this for me? Just wondering. It's not life and death, but I figured if anyone would know, it would be you folks here on this forum.