Is the method used to search for the owner of the gold piece correct, and is it permissible to dispose of it after one year from finding it, while ceasing to advertise?

The aforementioned item is a stray find (Luqata), and its ruling is that it is sunnah (definition) to announce it in places where people gather, such as universities. If its owner does not appear, the finder may benefit from it or give it as charity on behalf of the owner. If the owner comes later, he is given the choice between its value or the reward of the charity. What the questioner did by announcing it is correct, and he should re-announce it in the university transport after waiting for the academic year.