I found this in the Yahoo Dutch oven cooking group files
Methods on Cleaning/Restoring Old Cast Iron
Great Aunt Ginny's old cast iron skillet just came into your possession but
you'd rather not use it as it is, with fifty years of meal remnants on the
sides and rust growing underneath. Or perhaps you have serious food allergies,
and you don't know if the neat old cast iron dutch oven you just found at a
garage sale still has seasoning composed of foods that could put you in a
hospital, so removing all the unknown accumulated seasoning and starting over
is a must in order to be able to use it.
Here's a couple of methods to clean off that old gunk:
- Run it through the self-cleaning cycle of your kitchen oven. This is my
preferred, easiest, & most convenient method of burning off the old stuff, but
others may disagree particularly with regards to collectible iron, as there is
a possibility that the exposure to high temperature could warp thinner walled
older iron. Check to see if your oven manufacturer recommends removal of the
wire grates before running the self-cleaning cycle; otherwise the cast iron can
be placed right on the bottom of the oven during the cycle.
- Put it in your gas grill at the high setting of at least 500F. This works
for many, but in my experience, the prolonged high heat caused the paint to
peel off the inside of the grill -- SO was _not_ happy.
- Burn off the gunk in a hot campfire. I would be concerned for exposing the
iron to the extremes which could cause iron to crack -- avoid putting the iron
in a hot fire if it's cold, and be sure to allow for a gradual cool down.
- Soak & scrub in a vinegar/water bath of a 1:1 solution. This method is
probably the most gentle & natural, good for collectible iron, but it does take
longer and requires more manual effort to scrub works while it soaks. You'll
want to check your vinegar bath every couple of hours, and give it a scrub
while you're at it.
Experimentation shows that a weaker solution of vinegar will work also, it just
may take longer. Vinegar also assists in removing rust but one must take care
to watch that the iron is not overexposed to the vinegar as it may start to
deteriorate the iron as well. Be sure to rinse thoroughly with plain water when
done. Some recommend to neutralize the effects of the vinegar with a baking
- Treat with oven cleaner and let sit in a bag. Best results are achieved
with the really strong stuff. Make sure you apply the spray in a
well-ventilated area. I found this method too caustic for me, a whiff of the
spray caused me to gag & cough so it was difficult to apply.
- Soak in a lye bath. A big advantage of this approach is that once you set it
up, it is very handy for cleaning up many pieces of iron. However, at least
in my area of the States, lye is getting very difficult to purchase due to its
recent use in the manufacture of illegal drugs; lye has been removed from many
- Electrolysis. This is also a recommended method for cleaning many items and
those large pieces if you can find a large enough container. Once set up,
practically no scrubbing involved during the cleaning process.
- Bead blasting. Good results have been reported, but it could possibly be
damaging to collectible iron. I find it time consuming in a garage hood as you
can only spray a thin stream of beads at a time, which is tedious for a large
- Sand blasting. Again, caution is to be had with collectible pieces.
- Electric drill with a wire brush. A highly recommended brush by Ken Brown
is the Scotch-Brite Paint and Rust Stripper by 3M. Ken says these brushes last
a long time and do a good job. They're flexible so they allow you to get into
hard to reach places. The brush is 4 inches in diameter and has a 1/4 inch
shaft to fit on smaller drills.
As in all methods, once the iron is cleaned down to the bare metal, be sure to
cover it with oil as soon as possible, or else you will see rust start forming
before your eyes! And then proceed to season it with the High Temperature
Seasoning process as described & documented with photos by PumpDoc, aka Allen J.
COMMENTS ON HIGH TEMP CAST IRON SEASONING
High Temperature Seasoning
Other links for cleaning cast iron:
Wagner and Griswold Society
-- photos of various electrolysis set ups
Reconditioning & Seasoning Cast Iron Cookware
-- oven cleaner method described
Rust removal by electrolysis
-- photo of an electrolysis set up