Missed it. I had been converting a Lubitel (the gears slipped so it wasn't possible to accurately focus) to a pinhole, but I used a tiny drop of WD40 to loosen a tight screw, but some got on the shutter and jammed it.
I've heard soaking in lighter fuel can fix that, but as a non-smoker and with the decline in smoking and the rise of cheap disposable lighters I've not actually seen anywhere selling that for years!
I should try and get that sorted some time.