"File manufacturers recommend that you not touch the teeth of a rasp or file because the moisture from your hands will corrode and blunt the teeth over time. That's been impractical advice until now."
A little more of an explanation please, as it is somewhat vague as to whether you should or shouldn't? I just received this file, and one of my family members opened it up before I could get to it, and I suspect that they did touch the teeth of the file? What now? How do I remedy this?