Delete thousands of mails with one click on yahoo

Yahoo giving unlimited mail storage.But when some limit reaches(nearly 20000 mails) your account don't sent and receive any mails.This is due to yahoo giving unlimited storage.So to protect their server from unnecessary storage.So you must clear them daily.But you can delete 200 mails at one click(yahoo old Version).If you have a 10000 mails you have to press delete button 50 times.Its lot of time waste.So here is 4 simple steps to delete your thousands of mails.

• At the right top corner you will see 'switch to new yahoo mail'.So you will be turned into new version of yahoo.(click on images to see large view).
  
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• Then your yahoo account switched to new version.
• Then select delete check box there.Delete all.
• Then your mail box will be cleared.(You can also clear spam and trash.).
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• Switch back to old version.(Beside sign out).

Then you have cleared your mail box.But use this tip only those who are "Confirmed that getting 'ALL' unnecessary emails".