I repair old clocks. You will find that what you have isn't nearly as formidable as first seems. What I do is put on gloves and then put everything in a cloth bag, reach in and cut the restraining wire and slowly release you grip. There may be preservative on there that slows the release of the spring. I always wear safety glasses in the shop as well.
I have to admit that I like both the question and David's answer!
I have handled these in the past by doing something similar. Like David, I put on some good sturdy leather gloves first. Then I place the spring on the floor and cover it with a square piece of plywood about twice the size of the coiled spring. I press down on the cover with one hand while cutting the wire with the other, then slowly release pressure on the plywood. The spring will unwind somewhat suddenly, but cannot go anywhere. If the spring is too narrow to be able to reach it with the wire cutters, just slide the cover over far enough to be able to cut the wire. Some of the spring will unwind outside the cover, but will remain on the floor, uncoiling there.