def clean_up_columns(df):
    """Remove garbage columns from a pandas DataFrame.
    
    Drop rows and columns with only NA contents.
    Try to remove columns named "Unnamed", "User name", and "#";
        Pass quietly if these columns don't exist.
    """

    df = df.dropna(axis="columns", how="all").dropna(axis="rows", how="all")

    try:
        df = df.drop(axis=1, columns=df.columns[df.columns.str.contains("Unnamed")]
              ).drop(axis=1, columns=["User name", "#"])
    except KeyError:
        pass

    return df