declare
  v_temp varchar2(250) := '&test';
begin
  for i in 1..127 loop
   IF i between 1 and 47
   OR i between 58 and 127
   THEN
     v_temp := replace(v_temp,chr(i),'');
   END IF;
  end loop;
  dbms_output.put_line('value is: '||v_temp);
end;