This is a great way to “bulk delete” (clean out) a Gmail account when you are near your allotted space limit. Thank you to Laptop Mag for these instructions.
In the search bar, you can type the date in a YYYY/DD/MM format to filter out emails before a certain date. If you type before:2014/01/1, you’ll see a list of all of the emails you received prior to Jan. 1, 2014. You can also search by how old emails are. If you type older_than:1y, you’ll receive emails older than 1 year. You can use m for months or d for days, as well. If you want to delete them all, click the Check all box, then click “Select all conversations that match this search,” followed by the Delete button.