Giving New Life to Old Cast Iron

Jocelyn and Paul bring back a cast iron skillet to life using the self cleaning oven technique:

That's fascinating Andres. So how hot does the self cleaning oven cycle get? Could you just stick the pan in a fire and get the same cleaning effect?

I'll bet the rocket kiln would gitter dun!

Carla Burke wrote:I'll bet the rocket kiln would gitter dun!

That was my thought too! I was pondering how hot my woodstove might get (even in the firebox....)

I’d like to add my two cents to the seemingly endless ideas about salvaging, seasoning, and cleaning cast iron cookware. A bit of chemistry is in order to begin.

The “seasoning” on a cast iron pan, as many have said before me, is hardened oil. This means, for you chem buffs, “polymerized” oil. The oil molecules cross-link, creating a sort of pseudo varnish—a thin but relatively resilient, smooth(ish) surface that if used properly is (relatively) non-stick. All organic oils will polymerize over time, but (again for the chem buffs) it’s all about rate. Heat increases the rate of polymerization. Thus if you don’t want to wait weeks or months for that necessarily very thin layer of oil to harden on your new old Griswold, put the pan in the oven. Personally I’m a devotee of the long and slow oven method—200 degrees F or a little hotter for several hours. Repeat if your surface doesn’t perform well. I’ve used higher heats and thicker coats, and what I get is a surface less smooth than it could be, sometimes to the point of clumped, hard little oil droplets.

To clean a properly seasoned pan, use a bit of soap, lots of water, and if necessary a plastic scraper. While you can damage the surface with harsh soaps (like dishwasher soap) a bit of regular old dish soap won’t hurt a thing. Note that it is very possible to abrade seasoning off. Never use steel wool or stainless wool, and avoid the stiffer plastic scrubbies unless you have a very light touch. Never use salt. Salt is sometimes suggested in seemingly reliable treatises, but salt is a serious abrasive—no good. When finished at the sink, dry the pan thoroughly before putting away. I usually do the drying with a paper towel.

To recondition an old, rusted, crusted pan, burning in a wood stove or a self-cleaning oven are first rate choices. The key there is to not remove the pan from the fire or oven until it has completely cooled. Again, rate is key, but this time it’s crucial at the back end. Fast cooling will crack an iron pan. Once the firebox or oven has fully cooled, remove the pan and scrub lightly with 0000 steel wool or a green scrubbie and soap as necessary. Rinse real well and then season, and re-season, and maybe re-season again if the surface doesn’t look smooth and slick.

The pans in the picture have been in daily use in my kitchen for over 30 years. All started as old wrecks and were put in the woodstove for an initial burn-off, then cleaned and cared for as above. They are stellar kitchen companions.

A last note... Lard is my first choice for seasoning and most cooking because we render it ourselves and have it by the bucketful, but I’ve used other oils as well. So long as I followed the long and slow seasoning method, none have been a problem.

That is some really pretty iron.

Of late, I have used food grade flax seed oil (raw linseed oil) on my refurbished cast iron - 2 Dutch ovens and a skillet, so far.  I don't know if that's good, bad, or indifferent, compared to bacon grease or similar.

Here's my rationale: linseed oil oxidizes/crosslinks/polymerizes readily, even at room temperature.  That's what makes it a "drying" oil (usually hastened along in one way or another as "boiled" linseed oil - whether chemically with metallic salts or heated as "stand oil" - for a wood finish).

So, I've wiped on a thin coat of food grade flaxseed oil and put the iron in the oven at 350F or so, leaving it until the oil stops smoking.  It will stink up the house a bit.  It will smell like you've been using a heat gun to strip old oil-based paint.  It's better to do it on a day when you can open some windows and get a good cross breeze, but it's still winter-ish here, so that's a no go.  Maybe in a few weeks, but not now.

This is still experimental, so follow at your own risk.