How to print Gmail email without header information

First click on the printer button

Click cancel when prompted

Go to Developer Tools

Once you in Deveoper tools mode, you will notice there is a new pane below that show all the HTML code. Expand bodycontainer div class, when you mouse over the first table element, you will notice the section on top will be highlighted as well. This means that particular HTML code is the one that generated the highlighted section. Delete this table element.

And you will notice that Gmail header is no longer there.

Repeat these steps with other element such as

hr - to remove the seperator
first table element under maincontent div class - to remove message header
first and second tr element under message table - to remove sender and receipeint email.

After deleting the unwanted header information, you will get a clean message content. And you can proceed to print it.

Delete all emails before certain date for Gmail

To do this , you need to use some keyword when you search your email.

Example, let say i want to delete emails that contain sitemeter keywords that are older than 31, December 2011, i just enter "sitemeter before:2011/12/31" as shown below.

After that, click the box shown by the arrow to select all the emails and you will see one line of words just above your searched emails that let you select all the emails.

Once you select all the emails, just click the trash bin icon.

A confirmation box will pop up and just select "OK" and your emails will be deleted.

This example use just sitemeter as keyword and this might sometimes include emails that you don't intend to include. A better way is probably to use "from:reports@sitemeter.com before:2011/12/31" so only emails from sitemeter will get deleted. For more options, please refer to this link.