Hi pal, i picked up a 49 panel that had some deep deep rust . I went at it with a grinder ,and let me tell you ,it came off. right down to the metal. the grinder left some marks . then it's sand paper time. i worked through the grits of paper with a pom sander it all came out in the end. it's alot of work ,but it payed off .. The truck was in bad bad shape, i had to do floors, corners,doors . there's was big holes on both sides . ths inside rusted from front to back . if i can do it you can too. Reno