How can I get soot and grease off my hands?

There was a fire at a friend's home and I'm helping clean up the aftermath. I've got soot and grease on my hands and fingernails that no amount of hot water and soap will clean off. It's on the sides and undersides of my fingernails, in the wrinkles on my hands, and no matter how hard I scrub it won't come off. Is there a product that will take this off?