Tosefta zu Jeschijahu 5:31

There were two silver bowls on the top of the altar, one for water and the other for wine ; that on the western side for water, that on the eastern for wine. If the priest poured the wine into that meant for the water, or vice versa, he complied with legal requirements. Rabbi Yehudah said, "The bowls were of plaster, but had become black because of the stain of the wine ; and they had cavities like two slender snouts, by which the water and the wine went down into the pipe, and which they constructed when the Temple was built."The water and the wine go down to Shith, and are swallowed up in the midst of it, as it is said, In the holy place thou shalt pour out a drink offering of strong drink unto the Lord. So a place was made for it to be swallowed up in a consecrated way. Rabbi Yose says, Shith was hollowed to the abyss, as it is said, Let me sing of my beloved a song of my beloved touching his vineyard ; my beloved had a vineyard in a very fruitful hill ; and he digged it, and gathered out the stones thereof, and planted it with the choicest vine, and built a tower in the midst of it that is the Temple and hewed out a winepress therein that is the altar ; and also, hewed out a winepress therein that refers, too, to Shith. Rabbi Elazar ben Rabbi Zadok said, "There was a small passage between the graded ascent and the altar ; once every six or seven years novices went down there and collected thence the coagulated wine, which was like cakes of fig, and brought it up and burnt it in a consecrated way, as it is said, "In the holy place thou shalt pour out a drink-offering of strong drink unto the Lord." [Numbers 28] So as they poured it out in a consecrated way, in the same way they burnt it.