Please upgrade to remove one year emails, like 2014 inbox emails to be erased, how to do one shot ?
i think yahoo should upgrade short cut delete 2014 year inbox emails,
tick email for the year is too much.

The quickest way to do so from the web is to go to your inbox/folder, scroll a long way down, and then use the keystroke Ctrl+A to select all visible emails (or the top checkbox in the Yahoo Mail app). The further you scroll down, the more you can select at once.
You can delete a large number of emails at once this way, and I find it works best in groups of 1-2k. The maximum amount you can delete at once is 10k. Keep in mind that larger groups may take more time to delete. You can still empty the Spam and Trash folders all at once by clicking on the Trashcan icon that appears next to their names when hovering over them with the cursor. New Mail also allows you to empty entire folders at once using the arrow to the right of the folder; just click on it and select Delete all emails.