3,839. The Drain of the Altar

Hilchos Beis HaBechirah 2:11

The base of the altar had two nostril-like holes, called shittin, in its southwest corner. Blood that was poured on the altar ran through these holes, mixed into the drain that was located there, and flowed to the Kidron River.

Hilchos Beis HaBechirah 2:12

The floor by that corner of the altar had a spot one cubit by one cubit. This spot was covered by a slab of marble, with a ring set into it, by which that slab could be lifted. That’s where people could enter the shittin in order to clean them.