The UvA has entered into a partnership with the online service iLost. You could compare iLost to a search engine for lost items. The service can currently be used in the UvA buildings at Science Park, on the Roeterseiland Campus and in the University Quarter.
Go to iLost to see if your item has been found. On the iLost page (new window), select the campus where you lost your item.
You will often be able to retrieve the item the same day. Through iLost, you can make an appointment with Facility Services staff to pick up the item. In some cases, it may be possible to have the item sent by post to its owner.