def clean_strains_with_bad_dates(ird_df):
    """
    Removes strains that have bad dates (i.e. only MM-YYYY or YYYY).
    """
    ird_df['date_length'] = ird_df['Collection Date'].str.split('/').str.len()
    ird_df = ird_df[ird_df['date_length'] == 3]

    return ird_df