Ashtangasamgraha 12.31

12.31

kṛṣṇe sauvarcalaguṇā lavaṇe gandhavarjitāḥ |

romakaṃ laghu pāṃsūtthaṃ sakṣāraṃ śleṣmalaṃ guru ||

apāno jaṭharaṃ tena syurdāhajvaratṛṭkṣavāḥ ||

pravṛddhaṃ vardhayatyagniṃ tadāsau sānilo 'nalaḥ ||

vidyāt sulikhitaṃ vartma likhedbhūyo viparyaye ||

Black salt has the qualities of sauvarcala, but is devoid of its odor; / romaka salt is light; earth-salt is alkaline, increasing śleṣman, and heavy.
Apāna vāta [enters] the abdomen; thereby burning sensation, fever, thirst, and sneezing would occur.
That fire, accompanied by vāta, then increases the increased digestive fire.
One should know the eyelid to be properly scraped; in the reverse case, one should scrape again.