I have tried a dozen different ways of doing this. If I had vast quantities of all one size, I'm sure that drawing it through some sort of die with a little blade sticking down, would be the way. But I get wire sporadically and in a variety of sizes. I don't bother stripping the thin regular household wire. I only strip down stuff where I can make $50 an hour for my efforts, because the material is worth more as number 1 Copper. I generally try to
sell the wire for
reuse , before deciding to recycle.
I have used a very sharp knife and drawn it along the wire, but it's just about impossible to run a straight line as it touches the twisted material beneath the insulation. It's very hard on the wrist and easy to have the knife slip and get cut by it.
I've found two machines really effective at this. One is my cordless Milwaukee circular saw. It is only useful for very heavy gauge wire, because it's impossible to make small stuff hold still. When the stuff is heavy
enough to remain in place with its own weight, this tool is highly effective. I run it till it just barely touches the copper. It's important to wear goggles because there are little bits of copper flying around.
On lighter gauge stuff, say the diameter of my index finger, I have found that my cordless Milwaukee grinder, with a thin, cut off blade, works amazingly well. It's the much safer option. I suppose both operations could be done with a corded model, but I don't piss my time away like that anymore. With cordless you're not constantly monkeying with the cord, and you're not likely to cut it.
Doing this with a circular saw is an exacting operation. I'm sure that I could do it 10000 times without injuring myself, but I have known many people that I would never allow to touch the saw.
Using the grinder is by far the safest option, especially if you're going with a corded tool. A wrong move here would probably just fling your cord out of the way, instead of chopping it in half. If you hit a finger with this, you're likely to get a little cut, but it won't tear your finger off. That's important to some people.