I did a dumb thing and lit a fire in the fireplace the other night without opening the damper. I know...DUH! Anyway, soot got everywhere in this house- on the walls, etc. I bought some "extra power" Mr Clean Magic Erasers then when I was getting ready to use them, read the back and it sounds like they might be too strong for a typical painted wall- has anyone ever tried them on a house wall? It's not all over the wall- actually it got on other things thenm rubbed off on the walls in some areas.