Anandakanda 2.1.354

2.1.354

sā vālukā śramaghnī saṃsekātsannipātaghnī /
<uparasaśodhana>
kāsīsaṃ bhāvayed gharme dinaṃ jambīrajairdravaiḥ //

that sand destroys fatigue, and when poured upon, destroys the fever of tridosic aggregation.
Purification of secondary minerals:
One should impregnate green vitriol in the heat of the sun for a day with the juice of jambīra limes.