Volume 3, Book 42, Number 608:
Narrated Ubai bin Ka'b:
I found a purse containing one hundred Diners. So I went to the Prophet (and informed him about it), he said, "Make public announcement about it for one year" I did so, but nobody turned up to claim it, so I again went to the Prophet who said, "Make public announcement for another year." I did, but none turned up to claim it. I went to him for the third time and he said, "Keep the container and the string which is used for its tying and count the money it contains and if its owner comes, give it to him; otherwise, utilize it."
Volume 3, Book 42, Number 609:
Narrated Zaid bin Khalid Al-Juhani:
A bedouin went to the Prophet and asked him about picking up a lost thing. The Prophet said, "Make public announcement about it for one year. Remember the description of its container and the string with which it is tied; and if somebody comes and claims it and describes it correctly, (give it to him); otherwise, utilize it." He said, "O Allah's Apostle! What about a lost sheep?" The Prophet said, "It is for you, for your brother (i.e. its owner), or for the wolf." He further asked, "What about a lost camel?" On that the face of the Prophet became red (with anger) and said, "You have nothing to do with it, as it has its feet, its water reserve and can reach places of water and drink, and eat trees."
Volume 3, Book 42, Number 616:
Narrated Suwaid bin Ghafala:
While I as in the company of Salman bin Rabi'a and Suhan, in one of the holy battles, I found a whip. One of them told me to drop it but I refused to do so and said that I would give it to its owner if I found him, otherwise I would utilize it. On our return we performed Hajj and on passing by Medina, I asked Ubai bin Ka'b about it. He said, "I found a bag containing a hundred Dinars in the lifetime of the Prophet and took it to the Prophet who said to me, 'Make public announcement about it for one year.' So, I announced it for one year and went to the Prophet who said, 'Announce it publicly for another year.' So, I announced it for another year. I went to him again and he said, "Announce for an other year." So I announced for still another year. I went to the Prophet for the fourth time, and he said, 'Remember the amount of money, the description of its container and the string it is tied with, and if the owner comes, give it to him; otherwise, utilize it.' "