You can delete a group of messages by selecting them in a queue, or by using the custom message filter. When deleting messages, you can choose whether or not you want to send a non-delivery report (NDR) to the sender.
Deleting a message from a queue causes the message to be permanently deleted from Exchange, and thus from any further processing. It is recommended that if you delete messages, you should have Exchange generate an NDR.
The custom message filter allows you to choose the characteristics of the messages that you want deleted. For example, you can use the Delete (send NDR) option to delete the 10 oldest messages in a queue.
Important Microsoft recommends freezing both the queue and the messages you want to delete before using the custom message filter to delete them. Freezing the queue prevents messages from leaving before you can delete them. Freezing the messages and then selecting Frozen in your filtering criteria will ensure other messages aren't accidentally deleted. You can freeze the messages manually or with the custom message filter.