When any such account is filed by a clerk of the court, sheriff or magistrate, the officer filing the claim shall declare further on oath that the costs in the case out of which the claim arises have not been recovered out of the defendants and that the defendants are unable to pay costs; and also that the fines and penalties theretofore collected by them have been faithfully and fully paid over to the county treasurer. In every case the magistrate shall exhibit the original papers in which costs have accrued.