Here are instructions for creating a white list of approved senders in your Postini Spam Filter.  If you follow these instructions you will no longer have specific emails stuck in the filter unless the message contains a virus.

Open a web browser - e.g. Firefox and go to login.postini.com
Log in to Postini using your email address and password.
In the upper right corner locate and click "My Settings".

In the Junk Settings section of the My Settings window, click on "Approve Senders"

To approve a single email address use the left most box called "Approved Senders".  Just click to create a new line of text and enter the email address of the user, for example joe@somewhere.com.

To approve an entire domain of users like Cesa12 then use the "Approved Domains" box.  Just click to create a new line of text and enter just the domain such as cesa12.k12.wi.us.  No slashes no www nothing but the domain.

To approve a mailing list such as everyone@csdk12.net use the "Approved Mailing Lists" box.

Be sure to click the Update. . . button under the box where you have made changes.