How to Clean out Your Gmail InboxSteps
1. Open your Gmail account
In the search box, type "in:inbox is:read" (without quotes) and click the Search Mail button. You will now see the 20 most recent emails you have actually read.
Find the "Select" links just above the table of emails. It will say, "Select: All, None, Read, Unread, Starred, Unstarred".
Click on the word "All" to select all the emails that match your search. All the emails on the page should now be checked.
Click the link at the top of the list that says, "Select all conversations that match this search." This will make sure you have selected even the messages that don't fit on the page.
Click the "Archive" button at the top of the email area. Now all of your read emails have been saved to your archive, where they can be searched but where they won't clutter up your inbox.
Decide how far back you want to check your unread emails for important messages you might have missed. This will depend on how much time you have to spend on the project, and how fast your unread email tends to accumulate. 1 to 3 months is a good rule of thumb. If the email is older than that, either it was important enough that the sender will try to reach you again, or it no longer matters. For illustration, let's choose a date of August 1st 2009.
Type "in:inbox before:2009/08/01" (use whatever date you have chosen) in the search box, and click "Search". The format of the date is important. It must be in the form YYYY/MM/DD, with all 4 digits of the year listed first, then the month with two digits, and finally the date with two digits.
Select all of these messages by clicking "All" then "Select all conversations that match this search", just like you did above.
Take a deep breath, and click "Delete".
Confirm that you want to delete all messages. All those messages are in your trash. Hooray!
Click "Inbox" on the navigation bar next to your email list. You should now have nothing but the most recent unread messages.
Scan through your unread mail for important messages you may have missed.
Read the important messages, deal with them, and archive them to get them out of your inbox.
Search for "in:inbox is:unread" to get to all the messages remaining. Select all and delete using the methods described above.
Congratulate yourself, and resolve to never let your inbox overflow again! Read your emails and respond, archive, or delete them promptly from now on.