def clean_heroes(heroes):
    temp = heroes.copy()
    temp = temp.replace('-', np.NaN)
    temp = temp.replace('No Hair', np.NaN)
    replace_neg = lambda x : x if x > 0 else np.NaN
    temp['Height'] = temp['Height'].apply(replace_neg)
    temp['Weight'] = temp['Weight'].apply(replace_neg)
    return temp