I use wire strippers that I got at Radio Shack many years ago. You can set the gauge of the wire so that it only cuts the sheath and not the wire itself.
Now - that works great on the individual wires, but these cables have a secondary outer sheath that goes around both of them. That, for me, is a pain in the a**. That's what taking the longest time for me to do, is get that outer sheath off. Hopefully I'll get better at it. For now, I cut all the way around with a sharp edge at the place where I want it stripped to, I score the length of the to-be-stripped area with a sharp edge, I try to work the area where I first cut around it free enough to get a pair of pliers on it, and then I pull on it until it peels off.
