Slight pollution is removed by washing with pure water accompanied by certain prayers and imprecations on the Daevas, such as: "I contend with thee, O evil Angromainyu; away from this dwelling, away from the fire, the water, from this place, from all the blessings which Auramazda has created. I contend against pollution, direct and indirect; against the unclean spirits; I contend against the Daeva Andra, Çaurva, Zairicha (p. 169); against the Pairika, who goes to the water, the earth, cattle, and trees," etc.[369] More serious impurities require ablutions with gomez, which in certain cases have to be repeated thirty times, with various prayers.[370] The most efficacious purification, which removes even the worst taint, is that of the nine nights. This can only be performed by a priest, who knows the law accurately, can repeat the sacred word by heart, and speaks the truth. A special place must be constructed for it; thirty paces (which are equal to ninety times the length of the foot) from the fire, the water, and the sacred bundle of rods. In the middle of this space nine pits are dug in the earth, and round them twelve furrows are drawn with a metal instrument. The purifier sprinkles the person who requires cleansing (who is entirely naked) with gomez, from a leaden vessel, with many prayers. He is then rubbed fifteen times with earth; he must then wash himself at each of the nine pits once, twice, thrice with water, after which he is fumigated with fragrant wood. Then follow washings with water and gomez in the third, sixth, and ninth night. "After this," says the book, "the purified person shall bring water of purification to the fire, hard wood, and perfumes; he is to utter praises to Auramazda, to the Amesha Çpentas, and to the rest of the pure ones--so will the man be purified." The purifier must be rewarded for this purification; according to the measure of the man's property the payment rises from small cattle and cows to camels; "in order that the purifier may go away contented and without hatred." Instead of cattle, goods of another description can be given. "But if the purifier goes away discontented, the wicked spirit of impurity comes again into the purified persons, and they are impure for evermore."[371]