What Is The Treatment To Get Rid Of Dirt Patches On The Back?

Ok this very disgusting and I'm ashamed to say it but I have this dirt patch on my back and I've tried everything to get it off. It's from carelessness in my childhood. When I get in the shower and scrub, it doesn't come out. Now that it's summer, I want to go to the beach. But not with this disgusting dirt on my back. Do you think alcohol will take it out? Do you know of any other ways of getting it out? HELP!