Abu Dawud
Zakat
Book Number: 003 / Hadith Number: 1702
Narated By Zayd ibn Khalid al-Juhani : The Apostle of Allah (pbuh) was asked about a find. He said: Make it known for a year. If its seeker comes, deliver it to him, otherwise note its container and its string. Then use it; if its seeker comes, deliver it to him.