The lost Items of Makkah are not to be taken into possession
Question :
Is it permissible for me to pick up a lost item in Makkah Al-Mukarramah and take it and announce it in the area where I live, or is it obligatory on me to announce it at the doors of the mosques and the stores and other places in Makkah Al-Mukarramah?
Answer:
The lost items of Makkah Al-Mukarramah have a special situation in that it is not permissible for anyone to pick them up, except for whoever wants to always announce them or turn them over to the authorities who receive the likes of these possessions. This is due to the statement of the Prophet ﷺ:
"It is not permissible to pick them up (lost items in Makkah) except for whoever will announce them."
The wisdom behind this is that the lost items, if they remain in their places, their owners will probably return for them and they will find them. Based upon this, we say to the brother that it is obligatory on you to announce the item in Makkah Al- Mukarramah in its place and the area around it, like the doors of the mosques and the gathering places. If you cannot do this, you must submit it to those who are specifically designated to receive this lost item and other things.
Source:
Ash-Shaykh Ibn 'Uthaimin
Fatawa Islamiyah, Vol. 4 Page 309