[0] mine looks far worse than this http://forums.macrumors.com/attachments/image-jpeg.641961/
Do you work around mercury vapors, by chance? I wonder if it could also be something unusual in your sweat (perhaps from your diet)?
I destroy guitar strings on a near-weekly basis, despite all the anti-corrosion plating tech they have.
And Apple's service has topped "customer satisifaction" lists for years on end.
I'm not a shill, I promise. I just really like my Discover relationship.
I've owned 3 different models of iPhone and the premium support (if you pay it) is worth the price, aside from the issue of booking a time I always leave the apple store with my device fixed or replaced, I never have to come back another day and they always take my complaint very seriously (even showing me diagnostics indicating potential other issues I had not noticed).
I cannot fault Apple's customer service at all, in fact, it's why I still buy their phones instead of going through the impressive hoops I used to go through with sony-ericsson and nokia phones.