Ghee separately or cocanut separately should not be the offering. Why then nei thengai is offered neivedyam? The three eyed cocanut represents Lord Siva and cow’s ghee represents Mahavishnu i.e Lord Krishna also called gopala. The joint blessing power of siva and mahavishnu is considered as joint blessing power otherwise known as sastha alias ayyappa. Hence both cocanut and ghee should be given as offering to ayyappa.