Uses the type of field (from the mapping) to
        determine how to clean and format the cell.

def clean_cell(self, cell, cell_type):
        """
        Uses the type of field (from the mapping) to
        determine how to clean and format the cell.
        """
        try:
            # Get rid of non-ASCII characters
            cell = cell.encode('ascii', 'ignore').decode()
            if cell_type == 'D':
                cell = datetime.strptime(cell, '%Y%m%d')
            elif cell_type == 'I':
                cell = int(cell)
            elif cell_type == 'N':
                cell = Decimal(cell)
            else:
                cell = cell.upper()

                if len(cell) > 50:
                    cell = cell[0:50]

                if not cell or cell in NULL_TERMS:
                    cell = None

        except:
            cell = None

        return cell