Had 1.5 hours available, so I fired up the air compressor and got to work knocking all the undercoating off of the passenger side inner fender. If you haven't used a needle scaler, you need to try it. A needle scaler gun is super cheap on ebay (like $30-40 shipped) and does a nice job in a reasonable amount of time. The passenger side inner fender took one hour and 15 minutes. I will never use a torch and scraper again...