I did this on my friends 87 Ram 150, We used a straight grinder with a cutting blade. It worked real good. But be careful not to get too close to the body or you will cut into it and have to use more bondo. After cutting the tabs off smooth them down. Spray some primer over it Or fill with a little bondo if you cut to deap. Sand the imporfections then another coat of primer, then wet sand. We did this right before we painted the whole truck so the other paint was not a issue.