def process_cols(df,
                 excl_cols=['PAGE', 'TOTAL', 'AVG GRAMS'],
                 ren_cols={'DRUG CODE': 'DRUG_CODE',
                           'DRUG NAME': 'DRUG_NAME',
                           'BUSINESS ACTIVITY': 'BUSINESS_ACTIVITY',
                           'TOTAL GRAMS': 'TOTAL_GRAMS'}):
    """
    drop any unused columns and do some renames
    """
    df = df.copy()
    use_cols = sorted([x for x in df.columns if x not in excl_cols])
    df = df[use_cols].rename(columns=ren_cols)
    return df