My hiking boots are quite dirty and muddy - good thing to have a shoe cleaning rug with a slave's face in the middle! I rub the hard deep-treaded soles over his face and then make him stick his tongue out! He has to lick all the dirt and mud from my boot soles and gets his face crushed by my weight in between - he knows he better obeys and endures - as these boots could break all bones in his face easily, so he doesn't want me to get mad!