Techniques for assisting owners to remotely administer their digital content items stored at non-owners' personal computing devices. The techniques involve identifying owned content items from among content items stored in a synchronization replica that is synchronized with synchronization replicas at the non-owners' personal computing devices. The techniques further involve allowing owners to remotely perform certain administrative actions on owned content items. For example, in response to a command initiated at an owner's personal computing device, a network signal or signals can be sent to a synchronization agent installed on the non-owners' personal computing devices to automatically remove all owned content items from the synchronization replicas at the non-owners' personal computing devices. For example, the generation and sending of such signal can be performed by an online content item storage and synchronization service that synchronizes a server-stored synchronization replica with the synchronization replicas at the non-owners' personal computing devices.