The trustees of any cemetery, as hereinafter defined, may change or improve the condition of any burial lot in a cemetery, under the management or control of such trustees, if such burial lot is overgrown with weeds or is otherwise so unsightly as to seriously disfigure the burial ground. The trustees of any cemetery may also remove or repair any monument, curbing, marker or other property placed or located on any burial lot in a cemetery, except metal markers provided for war veterans as provided in section 80-107, which has become so unsightly, dilapidated or decayed as to disfigure the rest of the cemetery, if the owner or owners of record, or their next of kin, shall fail to do so within thirty days after notice is given as is set forth in section 12-802. Metal markers provided for veterans graves may be moved on the grave for the purpose of permanent placement.