Knock out the grease fitting, and cut off the boot, this will be fiery and smelly. You'll need a torch with oxygen, and a cutting tip with an oxygen blast lever. After that it's just like cutting/burning anything else with a torch. Heat it cherry red, oxygen blast it to blow out the molten slag and start cutting. When you run out of molten stuff to blast out, go back to heating, and repeat.
Basically blow a hole through the top, and that will let the joint itself fall out. Then air hammer the husk into pieces, or smash it inwards, or just pound it down. Depending on the c-frame adapters you have, you can press the husk downwards as well while it's still hot. Usually it's a 20 to 30min process to cool it back down. I like to douse it in penetrating oil.