hi guys,over the winter my outside vent pipe filled with ice/snow and then the ash built up and formed a solid block.i had to remove the bottom cleaning cap to let the stove vent(was filling back up inside the stove)anyway,i had to let it run for a day before i could unclog the pipe.the ash soot stained my vinyl siding on the house.i tried to pressure wash it with 3 different solutions i got at home depot.made it lighter but still looks awful.anyone know a product or home remedy to use to clean it?