Delete old emails in gmail from a specific date.

I can perform a search with the following criteria in gmail.
before:2011/11/20 AND in:anywhere

How can I go to the next step and delete all those mails.
Google search for delete old mail from gmail don't return any thing useful.

Idealy I would like to create a filter with some search useing just the "before:" operator.
before:2011/11/20
I keep getting a Please "fill in some search criteria" message box.
To fix this you don't use the filters
Gmail creates a link for you to delete all the old mail, it is not very obvious. It appears just above the first message in the list of messages.

"All 20 conversations on this page are selected. Select all conversations that match this search"

If you are running short of space you could always buy some more from google
https://www.google.com/settings/storage/

gmail filters to search for mail from bidorby

This is essentially what I am trying to do in the Google mail.
http://mashable.com/2012/06/22/gmail-filters/

http://support.google.com/mail/bin/answer.py?hl=en&answer=6579#0

So the images show step for step how to search for emails from bidorbuy.co.za and then create a filter form that search to mark those emails as important.

If you click each image you can load a bigger high resolution version of it. That should make thing easier to see.

First I click the gmail search drop down to show the advanced search.

The advanced search will show up like this

Next I type in the advanced search that I want to perform. 

In the From Filter I type in @bidorbuy.co.za. Then I click the search button at the bottom of the page.

that should perform the search and bring up all the mails that google has been automatically sending to the archive. You may need to change the date range that the search is performed over to include a period of more then 1 day. 

To create the filter I click the drop down again, it remembers my previous search so the from filter is pre-populated

At the bottom of the advanced search dialogue, there is an option to "create filter with this search". Clicking on that takes us to the filter dialogue. 

Now I can tell gmail to always make mail from bidorbuy as important and apply that filter to previous mails.