I did a lot of proofreading on my wife's papers when she was in graduate school. I often needed to inquire of her about meanings before I would change something. Simplest method I came up with was just to use 3 X's at the beginning of the word/phrase/paragraph/whatever. When I got with her and came back to it, Ctrl+F would find it (them, if multiples) immediately. It was so simple and fast, I would probably still use it.