You can view and remove messages in webmail.
You can enable webmail for an email account in the WebsiteForge Members area. By editing the email account and checking the "allow webmail" check box for the account this will allow you to login to webmail.
Once allow webmail is enabled you can visit your webmail site at webmail.YourDomainName.com
see screenshot:

Then click "login". (if you are unsure of your E-mail password you can click Here to watch a quick video on how to obtain your email password)
Once logged in you can view your messages. or Delete them. If you have already received your messages in a program like outlook and need to make some room for new messages you can either remove them in webmail, or can change your email client settings to not leave messages on the server for more than 1 to 3 days. (This is the recommended practice). If you wish to remove messages in webmail you can select all messages. See Screenshot:
See Screenshot:

Click on the "select arrows", then click "all". IF you wish to select all to remove the messages.
See screenshot:

Once all messages are selected you can click Delete. You should only remove all messages when you are sure you no longer need them, or they are already downloaded to a program like Outlook.