To remove all the commerce example data, you might use Administration Views + Views Bulk Operations + (Commerce VBO Views or Commerce Backoffice) to identify and delete all your sample products, orders etc.
Note that you might run into some situations where a product can't be removed since it's referred to by a line item which is part of a product; if this happened you might need to remove the orders and associated line items before removing the products, then the product types (etc - read as hypothetical example).
However, it's valuable being able to rebuild the site from basics, and in that case the route of exporting Views as Features as Pete suggests is a sensible one. This path will have more of a learning curve but has advantages for you longer term - eg it's much easier to track development stored as code than all globbed together in a DB, big advantages when dealing with unexpected problems later on ...