Cast iron wood-burning stoves are nearly indestructible, but they become unsightly if they've been neglected. They can develop a coat of rust, the seals leak and the firebricks crack. The bolts that hold the castings together may be weakened by corrosion. Restoring a cast iron heat stove may require some heavy work and persistence, but the results can be very gratifying, and your stove will be safer.
Clean the chimney, then move the stove outside if possible, because this will be a very dirty job. If you must work inside, isolate your work area with dust sheets, and vacuum the area frequently.
Remove the door seals (braided rope), and lift the door off the hinges. Clean ashes out of the firebox and remove the firebricks, being careful to notice how they are arranged. Vacuum the firebox.
If the bolts that hold the castings together are corroded, remove them and take the stove apart. Remove accessories, such as chromed decorative pieces, and have them professionally refinished.
Brush off the rust using a stiff wire brush, then follow up with coarse steel wool to get down to the "parent" iron. Severe rust may have to be removed by sandblasting.
Clean all the surfaces to be sure there is no dust or residue. Paint high-temperature spray paint. You may also use traditional sealers such as old-fashioned black stove polish.
Reassemble the stove replacing the fastenings with new steel bolts. Do not torque the bolts down too tight or you may crack the casting.
Clean the door glass with oven cleaner to remove the burnt-on soot. Carefully clean the seal channel and castings for the door. Mask the glass and the channel, then paint with high-temperature spray-paint or rub with black stove polish.
Reline the firebox with new medium duty firebrick. Cement a new seal rope in the door. Hang the door and close it on the new seal until the cement dries.
When you fire up your stove after painting or polishing there will be an odour. After a few fires, the odour will disappear.
The dust from cleaning your stove is harmful to your eyes and lungs. Wear a respirator and safety glasses.