The second neighbor covered his nose with his sleeve as he approached Gu Jiao's small courtyard, "Gu Jiao! What on earth is this?"
"Ammonium Nitrate," Gu Jiao replied. Seeing as her fellow didn't seem to understand, she put it another way, "Uh, soil with bird droppings!"
The second neighbor: "..."
Then, the corners of the second neighbor's mouth twitched, "Why do you need soil with bird droppings?"
Gu Jiao replied, "To boil."
His mouth twitched again and he looked at Gu Jiao in disbelief, "Not the boiling I'm thinking of, right? Boil in a pot?"
Gu Jiao nodded, "Yes, it needs to be boiled to obtain nitrate. After that, it is filtered and turned into saltpeter. You are here just in time to help me boil it."
The second neighbor was completely flabbergasted.
Of all the things a young girl like you could boil, why on earth would you want to boil bird droppings?
"Saltpeter is clean," Gu Jiao replied.
I don't care, I don't want to boil bird droppings!