Hazrat Ibn Sirin says that the pledged item will be sold only in the presence of the ruler.

Hazrat Khalid says that Muhammad bin Sirin sent me to Iyas bin Mu'awiyah, who was a judge, and said to tell him: I have wool (or similar) kept with me as collateral, and I fear that it may get spoiled (if left as it is). He instructed me to sell it.