If your knife has a problem, the seller may not be aware of it. Double-cutting does a pretty good job of hiding corrosion. I might not have noticed it had my knifesmith not pointed it out to me.
As I understand it, oxidation on S7 steel tends to remain on the surface rather than pitting the steel deeply. And, of course, catching it quickly helped. It cleaned up quite easily during the refinishing process.
so how can u tell if something is wrong.... im worried now <img src="/ubbthreads/images/graemlins/frown.gif" alt="" /> <img src="/ubbthreads/images/graemlins/confused.gif" alt="" /> <img src="/ubbthreads/images/graemlins/sad.gif" alt="" />