Personalty quickest way is gas and a match, but that is environmentally unfriendly... Although quite interesting my yard will buy burnt wire as #!. He explained that the smelters just burn it and the fire makes it clean ready to pour into the pot.. They use HEPA filters on the stacks to catch the fumes.

One way of doing it, is get a cast saw. Like the ones they use for cutting casts off of broken bones. My buddy used one for years.