I had the best luck with a torch and a putty knife. Used the torch to heat it up some, then the putty knife slides it right off. There was a little bit of a learning curve on how much heat to use. Too much and it get real gummy and nasty. After I scraped the majority of it off, I used a flap disc and sandpaper to finish it off. Have fun welding on the dirty ass galvanized metal.Sounds sticky! I’ve had good luck with the polycarbide wheels from harbor freight for removing undercoating without melting it and slinging it everywhere. Wire wheels and flap discs always make it sling for me.