Removal of undercoating

i have used a propane torch and a putty knife and a gasket scraper.
you only want to warm it up and make it soft, not burn it. if you use a grinder to clean it up after, remember there is asbestos in that old stuff, you don't want to make it fly.
my real question is why you want to remove it? the new stuff is not as good as the old stuff (imo) if you need to remove it to weld in subframe connectors or torque boxes, ok, but just remove what you need to, then use the new stuff to touch it up. i have removed the old stuff from a 57 and the bare metal underneath was perfect. Doug