I've worn these sneakers a lot lately and the soles are really dirty - completely covered in street dirt. I order the slave to lick them clean but he just acts disgusted and doesn't really get them clean - so I decide to punish him even more. I spit on the dirty shoe soles and make him lick the spit and dirt while I enjoy a cigarette. I also use the shoe soles as an ashtray and in the end I put my cigarette out in a spit-puddle on the soles - only to make the slave lick the dirt-spit-ash mix of course :-D