What do I do if I find a passport I'd reported lost/stolen?
Never travel on your passport if it has been reported lost or stolen. You run the risk of being stopped at border crossings, as Interpol keeps a record of all reports of lost or stolen passports.
You should return the passport to the Embassy of Ireland in Cairo for cancellation and return. The Embassy address is 22, Hassan Assem Street, Zamalek, Cairo.