The Compendium of Bheḷa 8.7.40

8.7.40

amlaṃ salavaṇaṃ sādhyamaṣṭabhāgāvaśeṣitam | kaṣāye tatra pīlūni kalkapeṣyāṇi yojayet ||

sour and with salt, it should be boiled until one-eighth part remains. / In that decoction, one should mix pīlu [fruits] to be ground into a paste.