Hide Unused Tags In Email

I have set up a basic order form using this plug in, on the order form is a button which when clicked adds a new row to a table, I want the form to support a maximum of 50 products so I have included the tags for the 50 products within the email. I assumed that each blank shortcode would simply be hidden but thats not the case.

Is there a work around for this?

Any help would be appreciated.

http://wordpress.org/plugins/contact-form-7/