It is the duty of the collector to proceed with all diligence to collect such insolvent taxes and to make monthly reports, payments, and settlements thereof with the Comptroller and county treasurer, as he is authorized and required to do in the collection of taxes which have not been declared insolvent, and he is entitled to the same commissions upon such insolvent taxes collected by him as are allowed by law upon the same character of taxes which have not been declared insolvent.