Bava Metzia 28 - How Lost Objects are Announced
Where in the Torah do we find the idea of returning lost objects by identifying marks? From: "... and it (the lost object) will remain with you until your brother seeks it out ...". Since you can't return it before he asks (seeks) for it, the word "seek" must mean something else - that you must seek out whether he is a liar or not by the use of identifying marks.
Thus a lost Get can be returned if the owner names a sign, such as a hole next to a specific letter.
During the time of the Temple, the finder would announce his find three times, on Passover, Shavuot, and Sukkot, but now it is announced in the neighborhood.