To disassemble the oven very carefully as the inner side of the bricks is black. Soot, it's not ash. She has a fat basis, and to launder it will be difficult.
If disassembled brick you will need it, then remove without tearing.
Begin to disassemble the stove pipe.
First dismantle the pipe on the roof. If the pipe was metal, it need to rock on and off. A brick chimney, you need to dismantle brick by brick. To help yourself you need a hammer. You can pick open a place of a laying trowel.
Dismantling pipe on the roof, go to the attic.
Continue disassembly of the pipe already in the house.
After the pipe is disassembled, the next step is to disassemble in a circle, starting at the top and working down.
Remove it from the oven, the stove, door and grates.
The last stage of disassembly is the analysis of the grounds on which stood the stove.