It is incumbent upon you and others who find any important lost property, to announce it for a whole year in the meeting places of the people two or three times a month. If its owner becomes known, it must be given to him. If he is not known, then it is yours after a year, because the Prophet (sallAllaahu 'alayhi wa sallam) ordered this. The exception to this is if it was found in the Haraman, in which case, so that its owner may become known. Or, he is to submit it to the responsible authorities in the Haraman, so that they may take care of it for its owner, based upon the words of the Prophet (sallAllaahu 'alayhi wa sallam) in Makkah:
"It is not permissable (to take) the things which are dropped therein, except to announce" (them). (Al-Bukhari No.2434 and Muslim No.1355)
and his words:
"I have made Al-Madinah sacred, just as Ibrahim made Makkah sacred" (Al-Bukhari No.2129 and Muslim No.1360)
However, if the lost item is something insiginificant and unimportant to its owner, such as a rope, a shoelace or a small amount of money, then it is not obligatory to announce it, and the one who found it is entitled to utilise it or give it in charity on behalf of its owner. An exception from this ruling is the lost camel and other animals which are prohibited, such as small beasts of prey, like the wolf etc., as it is not permissible to take them, based upon the words of the Prophet (sallAllaahu 'alayhi wa sallam):
"Leave them for they have their feet and their stomaches, so they can go down to the water and eat trees until their master finds them." (Al-Bukhari No.2428 and Muslim No.1722)
And Allah is the Granter of success.