What should I do if I find a passport I'd previously 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.

If living in Switzerland, Liechtenstein or Algeria you should return the passport to:

Passport Officer
Embassy of Ireland
Kirchenfeldstrasse 68
P.O. Box 262
CH-3000 Berne 6
Switzerland