Remove classes from field display When fields are rendered they have classes. For example here is the template for a taxonomy term reference field:

&lt;div class="&lt;?php print $classes; ?&gt; clearfix"&lt;?php print $attributes; ?&gt;&gt;
  &lt;?php if (!$label_hidden) : ?&gt;
    &lt;div class="field-label"&lt;?php print $title_attributes; ?&gt;&gt;&lt;?php print $label ?&gt;:&amp;nbsp;&lt;/div&gt;
  &lt;?php endif; ?&gt;
  &lt;div class="field-items"&lt;?php print $content_attributes; ?&gt;&gt;
    &lt;?php foreach ($items as $delta =&gt; $item) : ?&gt;
      &lt;div style="display:inline;" class="field-item &lt;?php print $delta % 2 ? 'odd' : 'even'; ?&gt;"&lt;?php print $item_attributes[$delta]; ?&gt;&gt;
        &lt;?php 
          print render($item);
          // Add comma if not last item
          if ($delta &lt; (count($items) - 1)) {
            print ','; 
          }
        ?&gt;
      &lt;/div&gt;
    &lt;?php endforeach; ?&gt;
  &lt;/div&gt;
&lt;/div&gt;


In the first line you'l see &lt;?php print $classes ?&gt;, in that $classes string there are some classes and I don't want. Obviously I can use php to str_replace in the tpl file to remove the classes I want, but that seems like a very wrong solution. What's the correct way to modify $classes?
You can implement hook_preprocess_field() in your template.php and remove the classes you want after checking the field name .

Update: As @tenken suggested you can also look into Display Suite module.