Simply locate the line for X-MailingID to know the saved search internal id.
A. MS Outlook 2003
1. Double click the email message.
2. Click View from the menu > select Options.
B. MS Outlook 2007
1. From the Inbox, select the Message
2. Right Click, select Message Options
3. The Message Options box will come up, check the Internet Headers.
C. MS Outlook 2010
1. Open the email message in its own window (by double clicking on the message).
2. Click File > Info.
3. In the righ-hand pane click on the Properties button.
4. Then Properties window show up with Internet Headers
D. Yahoo.com Account:
1. Right click on the email from your inbox.
2. Select View Full Header.
E. Gmail Account:
1. View the email from your inbox.
2. Click Arrow down for More menu located at the message itself.
3. Select Show Original.
Here is an example: