How to remove unused files efficiently?

I'm tasked with removing duplicate and unused files from a live CI application. While I've spotted errors, I'm unsure whether I can entirely move a file to the trash or just a portion of it. I've already reduced view files by 80%, and most Models are inactive. Currently, I'm focused on about 100 controllers (80 of which indicate prior versions in their names), each averaging 1500 lines. There are also four libraries with over 5,000 lines each.

For several PHP files in the controller folder, line 1 is as follows:


<?  if (!defined('BASEPATH')) exit('No direct script access allowed');
Would it be more appropriate as:


<?php  if (!defined('BASEPATH')) exit('No direct script access allowed');
Is this change sufficient to consider putting the file in the trash, or should there be other priorities to maintain?