def clean_minmax(dic):
    """
    Clean (set to zero) the MAX/MIN dictionary keys.
    """
    dic['FDMAX'] = 0.0
    dic['FDDISPMAX'] = 0.0
    dic['FDMIN'] = 0.0
    dic['FDDISPMIN'] = 0.0
    dic['FDSCALEFLAG'] = 0.0
    return dic
