I've lost many a note on old pencil transcriptions ... they've just disappeared as though erased ... durn, I thought they'd be useful for the boys I'm tutoring. Likewise, on some of the hectograph copies that got wet and smeared.
Old joke, with a false German accent, ala Groucho Marx "How da ya play zee not? The answer was a lip "buzz" by Harpo: "zzzzzzzzzzzzzzzzzzzz".
Thus, what notes have you lost? Be specific!