If you have the white spots, I do not understand why Apple wont sort them out for you. They have done/are doing all the others!
As for the 'corrosion', take it to a higher level with Apple. Has this happened to anyone else? If so, it sounds like an issue, if c
not, may be something contaminating from your skin, like an aftershave or something, and they are not going to help you. Give it some effort though, and just keep going to the next level with the complaint.
Marc