Clean up unwanted email messages in Outlook 365: Either view unwanted messages by sorting them alphabetically using the ‘From’ field, or searching for for an email address in the Search box. To sort, click on the filter at the top right of the main pane and select Arrange by – From (and then once, you have deleted emails return it to Date). To select lots of emails to delete from say Amazon. Click on the first, hold down the Shift key then Arrow key down to select a block to delete. To search, type the email address into the search box and delete from there