I just picked up a VERY clean Zeiss Ikon Nettar (518/16) with one problem, the shutter won't fire. I can cock the shutter, hit the shutter release, see the linkage move, but the actual shutter sticks. The shutter can be made to manually open and close by actuating the shutter winder lever. It takes quite a bit of effort though and the shutter moves slowly. The couple of the shutter blades seem dirty (slightly darker in colour), leading me to believe it may be the cause. Does servicing the shutter require the complete disassembly of the lens or can the just the front element be removed while the blades are cleaned with Ronsonol/Lighter fluid and a Q-Tip? A professional servicing would probably not be cost effective for this camera. I'm fine having the camera as a display piece, but it seems like such a waste.