瑜伽師地論略纂 2.105

2.105

Among the articles of purification, regarding 'kuśa grass': according to the customs of the brahmins, when they wish to set out on a journey and the like, if they see someone carrying it or someone leaves kuśa grass on the road, it is definitely an auspicious sign. As for 'bimba fruit': it is the bimba fruit, which is an auspicious fruit. As for 'conch shell': it is an auspicious conch; or the shell is just the conch, or conch and shell are different. As for the 'full vase': a vase filled with goods is an auspicious sign. In the Western regions, when people see this or someone gives it to them, they take it as auspicious and all give rise to joy; hence they are called pure conches [and treasures].