This laborious process results in grape-sized salt crystals forming in the top-layer while the water filters deeper. The salty soil is placed inside a tinjungan (cone-shaped tool made of bamboo) to filter out the undesired elements and mixed with seawater. The final mixture is left in the sun for several days to evaporate, resulting in the finished product.
Salt farming using these ancient methods is a waning industry. Working from sunrise to sunset usually nets around 5kg, and that's on a sunny day. 1kg sells for between Rp10,000 (USD$0.65) and Rp20,000 (USD$1.30). The younger generation are finding easier work elsewhere on the island. So this industry may not survive the next few decades. If you visit Bali, take the time to explore these traditional salt farms while you still can.