Sometimes, depending on a person's body chemistry, acidic hands (actually sweat) can soften the lacquer on the back of guitar necks. This is completely dependent on the person's body chemistry. I have bought guitars before with this problem, and in my case, my luthier buddy directed me to taks something made of a semi-rigid, but not sharp, plastic (I used a cut up credit card), and scrape off the grunge. In my case, after doing all of that, there was enough thinkness of lacquer for him to polish out. He did tell me that if the lacquer was deteriorated all the way through that he would have to refinish the neck. What is going on in the neck, is what also sometimes what happens to the lacquer under the right arm area when people with acidic sweat play with short sleeves. It not only wears away at the lacquer, it can almost "burn" the lacquer off. It is just body chemistry, not much you can do about it. I have met players with hands/sweat that is so acidic it can take less than 3 hours of playing for the strings to go dead. While it can be a lacquer issue, the lacquer must have been hard enough to polish out, so it probably wasn't a lacquer issue. Was this a used guitar, or is this the guitar you play most often? Is this the only nitro finished guitar that you own?
The poly- type finishes seem to resist this a lot better; Elixir strings will probably last longer as well for players whose body chemistry is this way. I personally don't really like the tone of the Elixers (regular Polyweb or Nanoweb), but don't have the acidic sweat issue.
Kostas
