If it is a smooth leather you could try a leather cleaner. There are good ones on the market that will remove things like this. If the it is suede you could use a suede brush on it and brush up the nap.
soot doors is provide to clean the outside of the water tubes and to remove the soot.
get a bath
Try salt and seltzer, but depends on fabric. Test on small inconspicuous area first to be sure it doesn't stain. Suede and microfiber should be cleaned with approved cleaner, can be found at Home Depot.
no
Just wipe it away with a dry paper towel.
with soap and water, maybe even DAWN plus bleach TM
Soot's plural is soot.
Soot is produced in incomplete combustion of hydrocarbons. Soot is black and leaves marks. It also causes health problems if in contact or inhaled!
You can use a fireplace cleaning kit to remove some soot from the base of your chimney.
use a Mr. Clean magic eraser. that will get anything off.
Soot is often produced when burning wood.
Chimneys in power stations use electrostatic precipitator to attract soot particles. Electrostatic precipitator are filtration devices that use electromagnetic charges to remove particles from gases.