You may find that you have a large spam folder but no way to delete it because it is not being displayed in your e-mail client. This page will show you how to subscribe to your Spam and Viruses folders in Outlook Express so that you can clear them out periodically.
Right-click on your Digital Crocus e-mail account and select 'IMAP Folders'.
Select your Spam and Viruses folders and click Show.
This should make your Spam and Viruses folders visible in Outlook Express - to clear your Spam folder just select all in the Spam folder (ctrl+a) and press delete.