If you see the sticking lever, a drop of lighter fluid on it's pivot will free it.
Apply the drop, work the camera and apply yet another drop. You may need two or three applications but it sure isn't brain surgery.
Use the head end of a straight pin or a toothpick to apply the solvent and blot any excess. The slight residue of the fluid will act as a lube
No spray on solvents of any kind should be used.