Well Worn Used Shoes?

So I was combing the 'wanted' section of craigslist the other day and noticed an ad from somebody wanting used shoes. Well worn, used high heels. He (I'm assuming it was a he) would pay $20 per pair. Why did I assume it was a he? Not sure. Seemed like some sort of fetish. Why would anybody want well worn used shoes? He specifically said to not bother cleaning them up or anything. What? Did he want to smell them or something? Check for DNA? I just can't wrap my head around it!