Arthashastra
श्वेत बस्त मूत्रे श्वेत सर्षपाः सप्त रात्र उषित अस्तक्र मर्क क्षीर लवणं धान्यं च पक्ष स्थितो योगः श्वेती करणम् ॥
The pastry made from white mustard seeds kept for seven nights in the urine of a white goat mixed with butter-milk, the milk of arka plant, salt, and grains (dhánya), causes, when applied for a fortnight, white colour.
english translation
zveta basta mUtre zveta sarSapAH sapta rAtra uSita astakra marka kSIra lavaNaM dhAnyaM ca pakSa sthito yogaH zvetI karaNam ॥
hk transliteration by Sanscript