In Vishnu temples theertha Prasad is given followed by sadari. Some archakas say do not apply the remaining theertha in the head bcoz it is an insult to sadagopan [sadari]. The reason being small portion of salaiva also will be mixed when the remaining theertha Prasad is applied on head. Butin big temples the will not tell anything like do not apply on head etc. Any citings from puranas???