It is highly advisable not to paint over soot. Though no damages have been reported, it is still highly recommended to get rid of soot before painting. There are numerous ways of removing soot. There are many reputed soot removers available in cans. The can has to be sprayed all over the soot and then clean it with a wet cloth. The soot will immediately disappear. Make sure you prime it after cleaning out the soot. Soot is generally formed near a fireplace or places where fire is present. It is also known as carbon black and it is a black colour pigment used in inks.