Stripping a cast iron skillet.

December 21, 2006 11:26 AM

I picked-up an old, cast-iron skillet which has seen better days and needs to be stripped and re-seasoned. Problem: I can't get it stripped down sufficiently.

The surface has a mottled, raised texture of old oil which I can't get stripped down. Scrubbing with a nylon scouring pad and hot soapy water doesn't do much. Using baking soda as an abrasive worked a little better, but it's still not enough. I'm hesitant to use steel wool for fears of scratching the iron too deeply.

Any ideas? Anymore I'm beginning to wonder if a nice coat of gasoline followed by a match might work ("It's cast iron, it doesn't care")

posted by nathan_teske to home & garden (38 answers total)

Why are you worried about scratching the iron? I'd use one of those stainless steel pot scrubbers.
posted by Good Brain at 11:31 AM on December 21, 2006

You need something acidic. Boil water with some lemon juice in it. Or tomato sauce. Soapy water won't do anything.
posted by spicynuts at 11:33 AM on December 21, 2006

You could set about it with a wire brush/sand paper, and don't worry about scratching it.
posted by zeoslap at 11:35 AM on December 21, 2006

Do you have a fireplace? A couple of weeks ago a friend of mine stuck a dirty cast iron skillet underneath a roaring fire in the fireplace and left it there all day. It was glowing orange when he took it out. All the crud was gone and the pan was just fine after a quick reseasoning.
posted by Addlepated at 11:35 AM on December 21, 2006

I used kosher salt to scrub mine the other day and it worked wonders.
posted by ubu at 11:41 AM on December 21, 2006

I'm with Addlepated. If you don't have a fireplace/firepit/grill, you can bake it in the oven for a long time. Even better if the oven has a self-cleaning cycle. Occasional swipes with a metal-bristled grill brush might help, during the gunk-cooking process.
posted by Lyn Never at 11:42 AM on December 21, 2006

My ex-father in law used to take the family cast iron down to the house's coal furnace, and toss the skillets and Dutch ovens in, one per night, on cold nights, to burn off baked on accumulation, and my ex-mother in law used to recommend this highly. I've done the same things in wood stoves and open fireplaces, but you do need to build a very hot wood fire, perhaps hotter than is safe in a small home fireplace, to get the desired effect. If you lack a coal stove or suitable fireplace, but have a self-cleaning electric oven, you could use that to accomplish much the same thing. Since you need to take the internal racks out to self clean the oven, you'll need a refactory brick or other high temperature insulator on which to set the skillet in the bottom of the oven during the self clean cycle.

Slowly bring the skillet up to high temperature in an electric oven, say 350° F for 30 minutes, then 475° F for another 30 minutes, so as to heat and expand the cast iron to avoid cracking. Then, while the skillet is still hot, remove the internal oven racks, set the skillet on a refactory brick, and start the cleaning cycle for the usual minimum time (4 hours and 20 minutes for most ovens). Let the oven cool completely after cleaning, at least 3 hours, before opening.
posted by paulsc at 11:46 AM on December 21, 2006

Thirding the bake it like a moped muffler technique. I've done this, works fine.
posted by QIbHom at 11:47 AM on December 21, 2006

Use the fireplace. That's how I fixed a Lodge cast iron skillet that had been mistakenly run through the dishwasher. It worked.
posted by cribcage at 11:48 AM on December 21, 2006

Spread oven cleaner over the interior and put it in your oven at the recommended temperature. While you're at it, clean the oven, too.

Here are varying bits of advice from a great Chowhound thread:

To remove burnt-on crud, put it on the stove, half-filled with water and bring it to a simmer, pour out the water and whisk it with a straw wok cleaning brush.

Get that pan screaming hot, and while it’s still damned hot, scrub it with a heavy-duty stainless steel scouring pad and kosher salt. Scrub it down to the bare metal, which is actually pretty easy when the pan is so hot. Then schmear it with shortening and crank up the heat again, for a while.

For ridged surfaces, use a welding brush with metal bristles.

Remove rust from old cast iron by baking in a self-cleaning oven or scrubbing with steel wool. Barkeep's Friend also works. Scouring powder with a halved raw potato works for stubborn spots, or use a slurry of vinegar and salt. For otherwise unremoveable heavy rust, CLR works very well, but smells awful. The Best is Carbon-Off, http://www.discoveryproducts.com/index_carbon_off.html

For pitted cast iron, have everything ground and polished out at a metalworking or cast iron shop.

1. Wear rubber gloves and eye protection while cleaning cast iron since the methods require using caustic chemicals.
2. Begin by spraying the pan with oven cleaner and putting it in a plastic bag.
3. After a day or two, take it out of the bag and scrub it down with a brass brush.
4. If all the grease doesn't loosen up right away, repeat the process concentrating cleaner on stubborn spots.
5. If you have several dirty items, soak them in a solution of one and a half gallons of water to one can of lye mixed in a plastic container.
6. Allow them to soak for about five days, then remove the pieces and use the same brass brush method to scrub them clean.
7. Remove mild rust with a fine wire wheel on an electric drill.
8. Crusted rust can be dissolved by soaking the piece in a 50 percent solution of white vinegar and water for a few hours.
9. Once the pan is clean, begin the seasoning process by warming it in the oven for a few minutes then applying a little shortening, vegetable cooking spray, lard or bacon fat.
10. Put the skillet back into a 225 degree oven for 30 minutes. Remove and wipe it almost dry to eliminate any pooled grease.
11. Place the pan in the oven for another half hour or so, completing the initial seasoning.
12. The seasoning process will continue with use, especially if you use it to cook fatty foods (bacon, sausage, fried foods, etc.) the first few times it hits the stove.
13. To clean after cooking, boil hot water in the pan. Let it soak for several minutes and then wipe dry with a paper towel.
14. Reheat the pan and apply just enough grease to wet the surface before storing.

Use the methods above only for cleaning iron.
Don't soak pans in a vinegar solution more than overnight without checking them because the solution will eventually eat the iron.
After cooking, do not use detergent or scouring pads to clean a cast iron pan since this will destroy the seasoning.

What You Need:
Rubber gloves
Eye protection
Spray oven cleaner
Large plastic zip bag
Brass brush

Barkeep's Friend or Bon Ami plus a ScotchBrite pad will clean any surface, and convert a mirror finish to brushed, which takes less care.
posted by KRS at 12:13 PM on December 21, 2006 [3 favorites]

I have couple of cast iron skillets that I've been working on intermittently for ages. That shit is caked. I've had great success spraying it with oven cleaner. It is still far from perfect but has considerably improved from its original state.

I've also heard taking an electric sander to it will work. Being without an electric sander, I've yet to test this method.
posted by schroedinger at 12:14 PM on December 21, 2006

Don't suppose you have, or have access to, a sandblaster do you? I've read about cast iron owners doing that when it's time to strip and reseason. I also read that sticking it in a fire can sometimes lead to cracking. Don't have personal experience but just passing that caution along.
posted by kookoobirdz at 12:16 PM on December 21, 2006

Wow, those are some pretty serious steps getting suggested. They might all work.... but the last time I had a cast iron skillet that needed stripping (it was rusty and caked and gross), I soaked it in coke - straight up regular coke - overnight. Worked like a charm. Didn't drink coke for several months after that....
posted by dpx.mfx at 12:20 PM on December 21, 2006

I've cleaned the outside surfaces of our old skillets with a drill and cup brush.
posted by buggzzee23 at 12:23 PM on December 21, 2006

Didn't drink coke for several months after that....


If you are afraid of that you'd want to stop drinking orange juice, tomato juice or anything with any citric acid in it at all. Coke is no more powerful than any of those things. Watch Mythbusters.
posted by spicynuts at 12:29 PM on December 21, 2006

Self cleaning oven will do wonders. Really.
posted by JayRwv at 12:42 PM on December 21, 2006

I'd use a harsh, acidic citrus-based solvent like Citrasolv to soak it. (That's my solution to any oily residue on anything tough enough to not also be destroyed by the solvent.)
posted by Zed_Lopez at 12:48 PM on December 21, 2006

I left a cast iron pan in oven cleaner overnight & it completely "rebooted" it back to factory gray. I was a little concerned about the chemicals in the oven cleaner but I'm OK so far.
posted by Wood at 12:52 PM on December 21, 2006

I used a mixture of Kosher salt and more oil to some degree of success.

Mix the two until you have a salt-oil sludge the consistency of wet sand. Apply elbow-grease liberally.

Of course, I also had a cast-iron skillet that couldn't be redeemed that way. The solution was the get a new one. (I figured that since I was going to re-season anyways, it might was well be on something fresh.)
posted by generichuman at 12:56 PM on December 21, 2006

Grapeseed oil, to be specific.
posted by generichuman at 12:57 PM on December 21, 2006

In the end there's no substitute for steel wool.
posted by Steven C. Den Beste at 1:10 PM on December 21, 2006

I know this is not really an answer to your question, but before you spend days scrubbing and many dollars on cleaning products, consider that one can purchase a brand new cast-iron skillet for less than $10, and that's MSRP, not street price. (Not that I would necessarily advocate buying new things rather than cleaning up old ones.)
posted by buxtonbluecat at 1:30 PM on December 21, 2006

You might also try Carbon Off; it is fast and easy.
posted by olecranon at 1:54 PM on December 21, 2006

Friend of mine had his sandblasted, tho to be honest the outside was caked not the cooking surface, still that pan is smooth as glass. It was a great find.
posted by Max Power at 1:55 PM on December 21, 2006

The heat the pan up method is the best though I'd love to see a pan that was walnut shell or bead blasted.

"I'm hesitant to use steel wool for fears of scratching the iron too deeply."

Avoid steel wool on the interior surface. You won't harm the surface but cast iron is softer than many steel wool wires. The wire breaks off in little tiny pieces (this is what makes cast such a good abrasive) which embed in the cast. They can then come back out during cooking. This goes double for steel wool cleaning pads which come pre-soaped.

KRS writes "Spread oven cleaner over the interior and put it in your oven at the recommended temperature. While you're at it, clean the oven, too."

Avoid harsh chemicals (all chemicals that you wouldn't mind tasting and eating really). Cast iron is porous and will soak up the chemical and then release it for months afterward while cooking. So salt, oil or Coke is fine, lye(oven cleaner) should be strongly avoided. You should never use even soap to clean a cast iron pan if you can possibly avoid it. You might find your pan has an off taste for a while.

buxtonbluecat writes ", consider that one can purchase a brand new cast-iron skillet for less than $10, and that's MSRP, not street price."

Which probably masses a 1/3rd of the posters antique. A good 8" skillet is going to go for 4-10 times that.
posted by Mitheral at 2:08 PM on December 21, 2006

Yuck on the chems. That can ruin a good iron skillet. Heat, baby. Having had skillets and Dutch ovens that had at least 100 years of crud on them, I'm with the folks talking about fire and heat.

My method. Coat it with crisco or olive oil (I like crisco/lard becasue it sticks to the sides),and let sit for a couple of days. That will penetrate the junk. Then burn them up in a huge fire. (I use a fire pit or steel wheel barrow tub).

The stuff that was penetrated by the oil will completely burn off, leaving you with a pan that is just as beautiful as the day it was cast.

Also, I don't recommend doing this indoors. You will be creating a grease fire which can get out of hand pretty quickly. Have a hose or some sand handy just in case.
posted by snsranch at 2:26 PM on December 21, 2006

<derail><credibility_check>Mitheral writes "Which probably masses a 1/3rd of the posters antique."

The Lodge I linked to weighs about 4lbs. An 8" skillet that weighs 12lbs??? That's some serious quality right there. Seriously unusable, that is. (Also, poster specified "old" - not antique.)

A good 8" skillet is going to go for 4-10 times that."

Heh. Have fun with your $100 premium-quality cast iron.</credibility_check><derail>
posted by buxtonbluecat at 2:30 PM on December 21, 2006

Unless it's a really nice Griswold and you really like projects, I'd tend to agree with buxtonbluecat.
posted by fixedgear at 2:59 PM on December 21, 2006

You will be creating a grease fire which can get out of hand pretty quickly. Have a hose or some sand handy just in case.

Whatever you do, don't turn that hose on. The grease fire will just splatter, grow, and spread. If you use any of the methods combining grease with fire, do it with a Class K fire extinguisher at the ready.

Thirding buxtonbluecat. It costs so little to get a good cast iron pan.
posted by nakedcodemonkey at 3:30 PM on December 21, 2006

I was able to clean a #10 dutch oven and lid to a pristine state by submerging it in a 5 gal stockpot and simmering it overnight in 4 tablespoons of dishwasher (because it doesn't foam much) detergent. I'd hesitate to use an aluminum pot, though. The cast iron would be fine, but the Al might suffer from an electro-chemical replacement reaction.
posted by jamjam at 3:32 PM on December 21, 2006

Have fun with your $100 premium-quality cast iron.

Yeah, I don't know where Mitheral shops. That's ridiculous.

But if we're going to talk about the danger of grease fires, I'll reiterate: I've successfully cleaned rust from cast iron by dumping it into hot coals, and it worked fine without applying any sort of grease. Save yourself from worrying about what type of fire extinguisher you've got; grease simply isn't necessary.
posted by cribcage at 4:19 PM on December 21, 2006

The Lodge frying pan that buxtonbluecat linked to is a good one (Lodge is the only company making good cast iron pans these days), but some of the antique stuff is a bit heavier, and stuff just seems to cook better in it.

It isn't like you can have too many spiders.
posted by QIbHom at 5:20 PM on December 21, 2006

Like JayRvw, the oven self clean cycle has worked perfectly for me. A modern version of the hot coal method that paulsc describes.

Oven cleaner "works" but does leave a really off taste in the pan. Acids (vinegar, lemon juice, etc...) don't work very well.

Bean (not sand!) plasted pans come out really, really pretty, but that will probably cost more than the pan is worth. But you never know, and phone calls to metal shops are free.
posted by bonehead at 6:14 PM on December 21, 2006

A well used, well-scrubbed cast iron pan has a very smooth surface that is great for pancakes and other things.
posted by theora55 at 9:01 PM on December 21, 2006

buxtonbluecat writes "The Lodge I linked to weighs about 4lbs. An 8' skillet that weighs 12lbs??? That's some serious quality right there. Seriously unusable, that is."

I just threw my 8" on the scale, it weighs 9.5 pounds so change to 1/2 from a 1/3rd. I inherited it from my grandmother but I've never seen one like it for less than $60 (not that I've been looking).
posted by Mitheral at 9:26 PM on December 21, 2006

Kosher salt and a little oil is what works for me!
posted by scooters.toad at 6:54 AM on December 22, 2006

Electrolysis

Another

I've done this to several way-far-gone pieces of cast iron. Works amazingly well.
posted by killThisKid at 9:24 AM on December 22, 2006 [1 favorite]

"... Bean (not sand!) plasted pans ..."
posted by bonehead at 9:14 PM EST on December 21

The process that I think bonehead is talking about here is generally referred to as bead blasting, for the glass, plastic or metal bead media that are often used in this kind of abrasive air powered cleaning method. Conceptually, it is like sand blasting, except the blasting media is chosen for hardness, size, and abrasive characteristic, so as to maximize the cleaning effectiveness of the operation, and minimize damage to the part being cleaned. Blasting media can be as soft as pulverized walnut shells to as hard and abrasive as ceramic pellets. Some blasters use metallic pellets, such as steel or bronze beads, to produce peened surfaces, which is a type of surface hardening treatment, and this is something you want to avoid with the common grey cast iron normally used in cookware, as it will adversely affect the heat transfer properities of the piece, and perhaps make it more vunerable to cracking in use, as it makes the cast iron surface somewhat "work hardened."

Done properly, bead blasting with a soft blast media which is frequently changed, or used in a "single pass" system, can be an effective cleaning method for metals, but I'd hesistate to recommend it as a cleaning method for cast iron cookware, for a couple of reasons. First is the work hardening problem discussed above, if hard media and high pressure air is used in a high velocity blaster. Second is that unless the blaster is a single use media type machine (very expensive), the blasting media becomes quickly contaminated with the removed dirt being blasted away. Your skillet being "cleaned" in a blast machine that has been processing solvent treated auto parts all day, probably is going to leave some residual materials that you'd rather not be putting in your mouth. It may look clean to the eye, but it may smell and taste "off" for good reason, and it may not season properly. Finally, bonehead is right in saying that unless you work in a shop where there is a bead blast machine, the shop charge for doing the process will probably exceed the value of the cast iron pan you want to have treated.
posted by paulsc at 12:06 PM on December 22, 2006