Section 532. Retention and destruction of certain recorded instruments

After twenty years have elapsed from  the  date  of  recording  a  deed,
  lease,  contract,  agreement, mortgage or a release of part of mortgaged
  premises any such instrument so recorded which has not been returned  to
  the  person  presenting  such  instrument for recording or to some other
  person authorized to receive the same, may be destroyed  by  the  county
  clerk  without  the permission of the commissioner of education provided
  any such instrument is photographed, microphotographed or reproduced  on
  film preserved for examination and use.