That's the problem with just softening it. Smears it around .
Almost like chemical paint stripping.
I guess I was maybe 14 or 15. I worked in my grandfather's shop.We had a big sandblast room. Did a lot of structural steel, cars you name it. We had a rotisserie to rotate body's. We hired a guy from Israel. one day a car comes in and in his broken English . You get for me 10 lbs cold ice he called it. A bottle of medicine alcohol and 6 beers for me.
Made it up like a paste. This best way, easy.
Well after about 10 minutes he picks up a hammer, and it's jumping off the metal in hunks.