I only romoved it where I had to, but my car was pretty rust free. Paint stripper works good, and is a lot less work too. (Use it outside!) Hit it with an old wire brush as it is working, a few times. Then use a putty kife. After all the metal work is done, I paint it and re-udercoat it with 3M body shutz and a shutz gun. The stuff dries hard, like the original. It doesn't have exactly the same texture (big deal) but I know it will last, and I won't have to worry about it comng off.