Cracking open a Kenner Batman figure

Posted in Custom Workstation

Dear Community,
I have recently entered world of action figures customization by successfully completing my first ever project that concerned transformation of an "Hydro Charge Batman" into a 1989 movie-like Batman, something simple and yet cool to start with.

Now, I am moving to something more ambitious. I still have a very old "Combat Belt Batman" AF which I would like to give a revamp touch instead of putting in the memory box. Basically speaking, my project is to dismember Batman, build a magnetic skeleton with a few adapted Geomag bars as limbs and some small spheres as joints, cover said structure with the original AF limbs (which I believe they are empty inside), use some modelling pastry to fill the holes and, at the end, painting the whole AF to give it a uniform look.

Here you may come in my help because I am unable to crack open my AF. As hard as I try to push the seam line of shoulders with a flat screwdriver, I keep failing at opening torso; crotch and hips seam lines are already opened but shoulders' seam line is a whole new matter. I have already read some tutorials hosted here at FR but I just wonder if there are some tricks that might be helpful for cracking open older AFs like Kenner's ones. I would like to thank in advance whomever can give me suggestion(s) about my inquiry.