The Prophet ﷺ said: He who finds something should call one or two trusty persons as witnesses and not conceal it or cover it up; then if he finds its owner he should return it to him, otherwise it is Allah's property which He gives to whom He will. (Using translation from Abū Dāʾūd 1709)
قَالَ رَسُولُ اللهِ ﷺ مَنْ وَجَدَ لُقَطَةً فَلْيُشْهِدْ ذَا عَدْلٍ أَوْ ذَوَيْ عَدْلٍ وَلَا يَكْتُمْ وَلَا يُغَيِّبْ فَإِذَا وَجَدَ صَاحِبَهَا فَلْيَرُدَّهَا عَلَيْهِ وَإِلَّا فَهِيَ مَالُ اللهِ يُؤْتِيهِ مَنْ يَشَاءُ