To delete one or more certificates, open the certificate manager by selecting
Tools -> Manage Certificates... option from the menu bar. This
will open the Manage Certificates dialog.
In the Manage Certificates dialog, select or highlight the certificate(s)
that you want to delete, and click on the Delete button. A confirmation
dialog will be displayed, asking, if you really want to delete the selected
certificates. Choose Yes to delete the certificates permanently
from your trusted certificates database. Select No to cancel the
delete operation.