Both the stones of the Altar and the stones of the ramp [were quarried] from the valley of Beis Karem. And they would dig beneath virgin soil, and bring from there whole stones which had not been touched by iron, for iron renders unfit [simply] by touching, and by being nicked by anything.  If one of [the stones] was nicked, it is unfit, but the rest of them are [still] fit.  And they would reface [the stones] twice a year, once on Pesach and once on Succos. And the Heichal [was refinished] once [a year], on Pesach. Rebbi says: Every Friday they would clean [the Altar] with a [wet] cloth, on account of the blood.  They would not apply the coat of lime to [the stones] with an iron trowel, lest it touch [the stones] and render [them] unfit. For iron was created to shorten the life of man, while the Altar was created to lengthen the life of man; it is not right that the “shortener” should be lifted up upon the “lengthener.”