If you are fed up of multiple emails (10000 +) in your inbox and want to get rid of all of them, it is nearly impossible. As of now, there is no solution in an online mode however if you use any third party software like Mozilla Thunderbird, Outlook or AOL desktop, you can do it very easily. I have used Mozilla Thunderbird software which is an opensource software (Free) in which you can add as many email accounts as you want and then use it. This way you can access multiple emails in a single window and you don't have play login log out the game for multiple emails.