The title says it all, really. DDog (mud-magnet golden retriever) likes to snooze against walls and escapes into the sitting room to have a good shake after we've been on a walk has made a couple of the walls rather grubby with dirt and splatters. What sort of things do you use to clean walls that dogs have made dirty? I think we have bog standard paint on the walls (painted by previous owner) so not any of that fancy wipe clean stuff.