How to crack a Gi Joe torso without losing any parts:
There are a couple of basic ways to split an action figure torso when you're customizing. One is to slice it open with an x-acto knife. The other way is to use a vise to allow the pressure to crack the torso. I absolutely prefer the vice method rather than the x-acto cutting method for many reasons. For starters, it is really dangerous to cut into hard plastic with an x-acto knife - especially when the object you're cutting into is a small toy. You could injure yourself real quick like doing this. Besides risking damage to yourself, you also run the risk of creating a wider gap that can be problematic when you try to glue the torso together later on for another custom figure. So I don't recommend trying it this way.
The vise method is the best in my opinion. Until last night I had be doing the standard "wrap your figure in a cloth, position, and turn" vice method. The problem with that is the force of the vise tends to blow parts everywhere. And it's usually the little disk that covers the waist articulation point that flys away. Very inconvenient. So, being the innovator that I am. I solved this little problem with a sandwich baggie. Here's what I did:
I took the head and legs off and put the torso in a plastic baggie. I made sure to press the air out of the baggie and seal it properly. The baggie ensures that no parts will get lost once the torso cracks open. Then I wrapped exterior of the figure in a cloth while it was still in the baggie. The cloth is used to prevent compression damage to the figure. Next I positioned the figure in the vise so that each should touched each side of the vise. After that I turned the handle on my vise slowy until I heard a slight cracking sound.
I released it after that and found everything as desired and all in the baggie. Amazing how satisifying something so simple can be! So that's how you crack a gi joe torso without losing any parts!