Agniveshyagrihyasutra 1.1.1.10

1.1.1.10

samāvapracchinnāgrau darbhau prādeśamātre pavitre kṛtvā anyena nakhācchittvādbhiranumṛjya pavitrāntarhite pātre 'pa ānīyopabilaṃ pūrayitvā udagagrābhyāṃ pavitrābhyāṃ trirutpūyottareṇāgniṃ darbheṣu sādayitvā darbhairapidadhāti \

Having made two strainers of equal darbha blades with uncut tips, a span in length, having cut them from the rest without fingernails, having wiped them along with water, having poured water into a vessel shielded by the strainers, having filled it up to the brim, having purified [it] three times by straining with the two strainers whose tips point north, [and] having placed it upon darbha grasses north of the fire, he covers it with darbha grasses.