Emails sent through drupal/simplenews/mimemail have extra css automatically added???

It seems that dropping in a blank mail.css into your admin theme isn't enough to actually get Mimemail to not do any addition of css to your template. I found I had to override this preprocess function with nothing as well.

/**
 * A preprocess function for theme('mimemail_message').
 *
 * The $variables array initially contains the following arguments:
 * - $body:  The message body
 * - $mailkey:  The mailkey associated with the message
 *
 * See includes/mimemail.tpl.php for additional variables
 */

// ORIGINAL FUNCTION

function template_preprocess_mimemail_message(&$variables) {
  $theme = variable_get('theme_default', NULL);

  // Check for the existence of a mail.css file in the current theme folder
  if (!file_exists($styles)) {
    $styles = drupal_get_path('theme', $theme) .'/mail.css';
  }

  // If no mail.css was found, gather all style sheets
  if (!file_exists($styles)) {
    // embed a version of all style definitions
    $styles = preg_replace('|<link.*href="'. base_path()
                           .'([^"?]*)[?"].*|', '\1', drupal_get_css());
  }

  // Process each style sheet
  foreach (explode("\n", $styles) as $style) {
    if (file_exists($style)) $css .= file_get_contents($style);
  }

  $variables['css'] = str_replace(' ','', str_replace("\n", '', $css));
}

// OVERRIDDEN FUNCTION

function garland_preprocess_mimemail_message(&$variables) 
{
  // REMOVE ANY AND ALL THEMING MIMEMAIL ATTEMPTS TO IMPLEMENT
  // otherwise you'll get random css added to the newsletter
  $variables['css'] = "";
}

Hope this helps anyone else that might have this problem.