Undercoating removal recipes

I've done it with a paint scraper and a wire wheel brush. The dry ice sounds like an interesting idea, but I think it would be more effective if it were placed on the metal floor above the area you're trying to clear.

The other way I've done it is to score it with a paint scraper, spray with lighter fluid, and ignite it. Must be done outside. Car interior must be completely stripped. Can not be used around fuel, brake, and electrical lines. Not good for you to breath, not good for the environment. Will convert some undercoating to a molten state, so provisions need to be made for drips. Need to provide for flame control. Is definitely not PC.