Update: the shutter on a customer's Pentax K1000 jammed in my shop and I used a guitar pick to free it
Last Tuesday a guy dropped off his K1000 for a CLA and the shutter locked up mid wind at my bench in the shop. I had no proper spanner handy, so I slid a thin guitar pick under the speed dial plate and worked the lock loose without scratching the chrome. The camera fired clean after that and the customer picked it up Friday happy. Has anyone else used picks or other non camera tools on stubborn dials, and did it ever backfire on you?