How to set up automatic cleanup on the Junk-Email folder?

Thunderbird

1. Right click the Junk-Email folder and click Properties.
2. Select the Retention Policy tab.
3. Un-check Use my account settings and select the Delete messages more than 30 days old.
   
   
4. Adjust the number of days if necessary.
5. Click OK to save the changes.
   

Microsoft Outlook 2007 and 2010

1. Right click the Junk-Email folder from the Mail Folder view.
2. Click Properties.
3. Click AutoArchive tab.
4. Check the radio button named Archive this folder using these settings:
5. Check the radio button subsequently named
6. Select the desired clean-up period from Clean out items older than options.
   In our example, it is 1 Month(s)
7. Click OK to finish the setup.
   Note: If a dialogue appears prompting you that "There are no global AutoArchive options set", it is not harmful to click OK to by-pass the dialogue.