How to archive old orders in Drupal Commerce
Couldn't you just backup your database using phpmyadmin, doing a .mysql export of the whole database which would keep record of all orders in the commerce_order and commerce_customer_profile tables?

Then using phpmyadmin, just remove all rows from the commerce_order table, to wipe the slate clean.

In the future, if you wanted to add all orders back into the site, you could import the data from your backup.