Jeremiah 38:11

So Ebedmelech took the men with him
The thirty men, as the king ordered: as soon as ever he had got the grant, he immediately set about the work, and lost no time to save the prophet's life: and went unto the house of the king under the treasury;
from the gate of Benjamin he went to the king's palace, and to a particular place under the treasury; by which "treasury" may be meant the treasury of garments, or the royal wardrobe, under which was a place, where clothes worn out, or cast off, were put: the Septuagint represent it as underground, a cellar under the wardrobe: and took thence old cast clouts, and old rotten rags:
the Syriac version has it, such as cattle were wiped and cleaned with: and let them down by cords into the dungeon to Jeremiah;
for it was so deep, that men could not reach to put them into the hands of the prophet; and, had they been thrown in, they might have been scattered about and be out of his reach, who stuck in the mire; or they would have been in all likelihood greatly bedaubed with the mire.