Rasamanjari 5.54

5.54

tridinaṃ dhānyarāśisthaṃ taṃ tato mardayed dṛḍham /
rajastadvastragalitaṃ nīre tarati haṃsavat //

placed inside a grain heap for three days; then one should triturate it vigorously.
That powder, strained through a cloth, floats on water like a swan