How to delete the citation metadata?
I want to remove the citation metadata element completely from the dublin core elements. any help?

To remove the citation, go to /yourtheme/items/show.php and remove the whole section related to citations. It will look something like this:

<!-- The following prints a citation for this item. -->
<div id="item-citation" class="element">
<h3><?php echo __('Citation'); ?></h3>
<div class="element-text"><?php echo metadata('item','citation',array('no_escape'=>true)); ?></div>

Thanks. it is now removed

Hi Sheepah,

Do you have a way of removing the "use HTML" tick box in the Dublin core elements in the Admin console?

Patrick already responded to you in the thread you started for that question. That isn't really something you can change in a theme.