New Shoes!!!
However, I finally decided that they had given up the ghost, and needed to go to the place where shoes find their eternal rest. The shoe salesman at the shoe store even offered to throw them away for me. She acted somewhat horrified that a person would wear such ratty things. However, I think it was all a facade, and she was trying to take possession of them. I was frankly rather afraid that if I'd be held responsible if someone caught a disease from them. They've been drenched in human blood on several occassions when the wearer was working on some poor trauma patient. They've had their fair amount of exposure to the normal hospital pathogens. After 4 years, they are probably so toxic that they'll never decompose. Some archealogist will discover them and probably display them as a shoe mummy.