A method and an arrangement pertaining to an alarm-equipped valuable item storage space (1) includes at least one device (10-13) for the storage of valuable documents, banknotes or the like, in which a destructive agent (61) is intended to destroy the valuable documents (100) in response to a burglary attempt and/or manipulative action. In conjunction with the need to destroy the valuable documents, a destructive agent container (60,63) is opened so as to cause the destructive agent to move into a collecting vessel (50) within which a valuable document collecting device (30) is at least partially situated. The volume of a destructive agent is such as to enable the collecting vessel (50) to accommodate the destructive agent (61) in the absence of overflow. The destructive agent container (60,63) is placed above the collecting vessel (50) so that the destructive agent (61) will run or fall down into the collecting vessel when an alarm is triggered.