Just fixed the sticking shutter on my YashicaFlex C. For the longest I had to warm up the shutter by firing it bunch of times while covering the taking lens, but afterward it would work fine. I finally got annoyed and searched for a few guides online. I had 2 options, the complicated removing the front leather and entire lens assembly, or the take out just the front element. I opted for the 2nd but I had worried because I didnt have a spanner wrench. To my surprise, the front element rotated out easily with my fingernails! Cleaned the shutter with a Q-tip and a bit of Naphtha very lightly, and worked it a few times while reapplying more Naphtha making sure not to have it too drenched to fall on the rear element. Works like a charm now! I just hope I didnt screw up the focus as I didnt check the point where I first unscrewed it. I just screwed it back in until it was tight. haha