i have used regular black shoe polish (paste not liquid), fired up the stove...... Viola!!!!

I've never found a cold-apply product that will properly season
a wood stove so it won't rust again, and I've been blacksmithing
since before Homer was a pup and I'm a grandmother now, with work
in 12 foreign countries. To properly season the outside of a wood
stove, you need to build a slow fire in it and maintain it while
you apply raw linseed oil or unsalted lard, and this is done in
very dim light. If you don't have a stove thermometer or a Tempil
stick to tell you how hot the outside is getting, the old standard
is to get some oat or wheat straw and hold the end of a few straws
about 1/4" from the surface you are seasoning. If they blacken but
don't smoke or burst into flame, you're in the ballpark for correct
temperature. If you have a stove thermometer or Tempil stick in the
right temperature range, go for 700 F - 1000 F. You should do this
outside, because when hot iron is properly seasoned and "sealed",
the fat used does smoke off. It should NOT flash and burn, it
should sizzle softly, and it should smoke some. How much smoke you
get depends on how much you apply at a time, after all. When an
area ceases to smoke & the fat you apply just runs off, that
area is finished. Move to the next area. You need to overlap
application areas, of course. If the stove is in your kitchen or
similar place, open windows and set fans to suck the smoke outside.
Hoods don't work particularly well because they are trying to
affect too large an area. The process has to be repeated every
other year or so, depending on how hot you get your stove should
you use it daily. The hotter and oftener it's used, the likelier
you will have to do this annually. I know this isn't the answer you
want, but it is the best one.

A wonderful old man gave me his mother's wood cookstove. He told
me to season it with lard. First I tried paint, then stove black
(which rubbed off on everything and everybody) then I tried the
lard. Just use a little bit a time, until it gets absorbed,
otherwise you have a smokey stinky mess. But I have been using it
for 20 years and my stove hasn't rusted a bit. It's just like
seasoning a cast iron skillet.