Stool, in one place it is said that, "It is impure. If you touch, then you have to take your bath." In another place it is said: "This stool, particular, the cow dung, is pure. Cow dung is pure. If there is any impure place, if you smear over it cow dung, then it is pure." That is also injunction of the Vedas. Now, you cannot argue that, "One place you say that this stool is impure, and another place you say this is pure. This is contradiction." Sometimes people find this contradiction. But you have to accept, because it is injunction of the Vedas. That you are doing practically, every day.
Similarly, this bone, any bone, animal bone, if you touch, you have to take bath. You become impure. But this conchshell which you are sounding, vibrating in the Deity room, that is also bone. But you cannot argue that, "You say bone is impure. Why you are taking one bone in the Deity room?" That you cannot say. This is acceptance of Vedas, without any argument. And if you want to know why one is accepted pure and one is accepted impure, if you make, I mean to say, research, you will find that the Vedic injunction is right.