How do we search for all our archived messages in Gmail?Non-archived messages should not be displayed,Only the archived messages should be shown.
How to show all archived messages in Gmail?
gmail;gmail archive
In the Gmail search box, type-label:inbox -label:sent -label:drafts -label:notesand press enter. That should give you all your archived messages. Once there, select All and then click Select all conversations that match this search to ensure that all messages are selected. Click Delete.They'd still go the the Trash though so you'd have to empty the Trash as a final step. 