Kautilya's Arthashastra 14.2.9

14.2.9

kaṭukālābau valīgate gataṃardhamāsasthitaṃ gaurasarṣapapiṣṭaṃ romṇāṃ śvetīkaraṇam //

The paste, prepared from white mustard seeds which have been previously kept within a large bitter gourd and with clarified butter prepared from the milk of valli (a creeper) for half a month, makes the hair white.