Matsyapurana 17.18

17.18

darbhāsanaṃ tu dattvādau trīṇi pātrāṇi pūrayet
khapavitrāṇi kṛtvādau śaṃ no devīty apaḥ kṣipet //

First, three kuśa should be placed for the Pitṛis to take their seats on, and then kuśa rings should be placed in three vessels in which water should be poured, after reciting, "Om Śanno Devî." etc. Sesamum should be offered by reciting, "Om Tilo si," etc. after which sandal and flowers should be offered. The vessels for the Pitṛis should be made of any of the following materials, viz:—Lotus leaves, wood, conch-shell, gold and silver.—18-20.