Most of the times your gmail box gets stocked up with mails and it is a stressful task for most of us to start deleting messages one after the other.
If you've taken good note, you will discover that the Trash and the Spam folders in your Gmail has a unique property of automatically deleting old messages after a fixed period of time (30 days to be precise), this is done by the Auto-purge.

You can also get rid of unwanted and older email messages with auto-purge in Gmail in order to keep your mailbox clean.

If you have set your Gmail to archives all your newsletter subscriptions to a particular folder, then be rest assured that these unwanted messages will remain forever until you manually erase them but with auto-purging enabled, the older mails of a folder are automatically removed from your mailbox.


CHECK OUT HOW TO BACK UP YOUR FILES WITH GMAIL

Auto-purging has no special button to enable it for any particular folder but there’s a simple Google Script that will bring this missing functionality to your Gmail. The script will basically monitor messages belonging to a particular folder in Gmail and purge those that have exceeded the retention time.


ELIMINATE UNWANTED MESSAGES WITH AUTO-PURGE


=> Make a copy into your Google Drive.




=> Set the value of GMAIL_LABEL to the specific folder that you wish to auto-purge and PURGE_AFTER are the number of days for which you to retain a message in Gmail.
=> Go to Run, then Initialize and grant the necessary permissions. It is a personal script and nobody else will ever have access to your data.
=> Go to Run, then Install to install the auto-purge script.
=> Now your auto-purge is enabled.

Exit the Google Script and it will continuously monitor that particular Gmail folder you've assigned it to in the background.

To disable auto-purging later, just open the same script in your Google Drive and choose Run, then Uninstall.

http://www.etechvilla..com/2013/01/how-to-get-rid-of-unwanted-and-old.html