optimal way to remove unwanted js and css files from page

Have a look at the FOAD technique to get rid of stylesheets and scripts. It happens in your own theme.

You can take an alternate route and use stuff like Stylestripper module or Mothership base theme.

With reference to your question 'optimal way to remove unwanted js and css files from page', hope this approach works ::

1) Include your js & css files only under appropriate hook as per applicable

2) Use syntax like -

drupal_add_js (drupal_get_path ('module', 'module_name') . '/js/js_file_name.js' ); drupal_add_css(drupal_get_path('module', 'module_name') . '/css/css_file_name.css');

3) You can make use of syntax like this to set some settings variable & check in your js file before invoking your event inside the behavior

In module file ::

drupal_add_js (array ('module_name' => array ('variable_name' => some_value)), 'setting' );

In js file ::

   Drupal.behaviors.testName = {
     attach: function (context, settings) {
       if(typeof Drupal.settings.module_name != 'undefined' 
    && 
    Drupal.settings.module_name.variable_name == some_value){
      // Do SOMETHING
       }
     }
  };

4) If your code already included js & css files at places which could be done a better way, then you need to make the code changes accordingly. For example,

If we could include the js & css files in hook_node_view (based on D7 standard, say), then we should not include it from hook_init.

Hope it helps