Reread what Dave Kanger said. Carbon, i.e. soot, is not soluble in any solvent! When we use soap and water to clean something the soap forms a chemical bond with the stuff we are trying to remove and the water, thus making the stuff soluble. Organic solvents dissolve oils and greases making them removable. Soot is not soluble. You will have to mechanically remove it with either scraping, sanding or some other physical (mechanical) method.
The use of rubber or plastic erasers is another "mechanical" method because the eraser is abraded during use and the little bits of carbon are physical incorporated in the abraded eraser and held in the abraded bits by electro-static attraction. In my experience erasers are one of the most productive ways of removing carbon black. Try all different types, both with the grain and across. Be prepared to "use-up" more than one eraser. Pink pearls, white plastic and gum rubber erasers all work but some types work better in some areas than others. Go to an artist supply store and get some of the plastic putty erasers used for charcoal drawing clean-up. They work really well.
Best Regards,
John Cholin