Article 1038 of Civil Code

1 – The creditor may not derive benefit from the pledged thing without consideration. - He must exploit it fully in accordance with its nature, unless otherwise agreed. - The net yield obtained by the creditor and the benefit he has derived from using the thing shall be deducted from the amount secured by the pledge, even if it is not yet due, provided that the deduction shall be made first from the amount he has expended on preserving the thing and repairs and the charges he has paid, then from compensation due to him, then from expenses, and then from the principal of the debt.