I have an unsightly film around my stainless pan as shown here: frypan

What is causing this to happen?

And how can I remove the film? I have soaked it in soapy water, scraped it with a plastic scraper, and run it in the dishwasher several times, but I can't seem to get rid of the film.

UPDATE: the pan is an All-Clad stainless, fully-clad frypan: http://www.amazon.com/gp/aw/d/B00005AL8C

  • Is this something that occurred over time or is this something that happened only when you cooked something specific in it. If that is the case, what was it? – Jay Apr 7 '12 at 16:50
  • @Jay - I tried the technique of heating the empty pan in order to expand the metal and close up any microscopic cracks in order to prevent food from sticking. I must have overdone it because when I put in olive oil, it burnt and released quite a bit of smoke and left the residue. – Mike Eng Apr 9 '12 at 4:18
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    This picture you took is now the first google image search result for oil polymerization! ibin.co/52x7wepUiZhl.png – Phoenix Nov 23 '19 at 21:46

11 Answers 11


As others have already said, it appears to be polymerized oil. It happens when oil is left in the pan hot for a long period (temperature depends on oil), or smoking for not as long. However, lye probably isn't required to remove it.

Bar Keeper's Friend and a bit of scrubbing will probably manage to take this off. As an advantage, while getting BKF on your hands will dry your hands out, it won't cause injury—unlike lye.

Alternatively, a scouring pad and plenty of elbow grease will take it off as well (though will also leave shallow scratches in the stainless—it'll not be polished anymore). Or, similarly, a sanding block or sandpaper.

I wouldn't put an aluminum core stainless (or tri-ply) in an oven on the self-clean cycle. Those get very hot, somewhere around 900°F, and I'd not at all be surprised if the pan warped.

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    Bar Keeper's Friend is hands-down the best solution here, because it is a mild abrasive and rapidly scrubs away the polymer layer. Steel wool and elbow grease will work too, but they scratch up the metal, where BKF will leave a shiny polish. – BobMcGee Apr 10 '12 at 13:33
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    +1 I agree that a mild abrasive cleaner is the best solution. I've got a bottle of polishing compound meant for stainless steel (I don't imagine the brand matters much), and it never fails to remove this sort of thing. Can't say I've ever had any burned spots as big as those in the picture, but small ones happen from time to time. – Caleb Apr 10 '12 at 15:23

This looks like half-polymerized oil. It happens when you overheat a layer of oil in the pan.

It won't come off through scraping. If you insist on removing it mechanically, you will have to try a polishing brush on a Dremel or something similar. I remove these chemically. Make a lye concentrate in the pot and let it sit overnight. Rinse very (!) thoroughly. This works well on stainless steel - but don't ever use it on aluminium pots!

If you don't have lye, you can also try a weaker alcali solution, like baking soda. But I doubt that it will be enough to remove the stuff.

To avoid it from happening again, don't overheat. This happens if the pan is left empty at at least 200°C for a very long time (or higher temperatures for a shorter time). There is no cooking method which requires this. Most things done in a pan are OK at around 150 to 160°C - if you are making steaks, sauteeing, etc., you should start using lower temperatures. Wokking needs these high temperatures - but first, a shallow SS pan is not good for wokking, and second, you should have more oil in there while preheating, and then move vegetables continiously around the pan while wokking. So this layer shouldn't happen at all.

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    I will just add that what the OP has essentially done is "season" that stainless pan. Mostly people do this only for cast iron pans, and you can't tell it's brown like that because of the dark iron surface. There are also non-stainless steel pans (like a good wok or crepe pan) that benefit from this kind of seasoning, and until the seasoning burns to black (it will eventually), a uniform brown color like that is highly desirable as it makes them non-stick. – bikeboy389 Apr 8 '12 at 14:48
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    You seem to love lye :-P. Stainless pans often have aluminum inside (or sometimes just a disc on the bottum). If there is any tiny exposure of that aluminum, lye is going to be a very bad idea. Bar Keeper's Fried or a scouring pad is much safer. Also, 200°C is an acceptable frying temperature (depending on oil). And steaks are done higher than 160°C. – derobert Apr 8 '12 at 18:56
  • @derobert I am 100% sure that a scouring pad doesn't work. I have spent lots of time proving it :( Never tried Bar Keepers Friend, but it seems to be just another acid. I have also tried concentrated vinegar (20% acetic acid) without success. BKF may be better, but I doubt it. This stuff just doesn't react with acids. I agree that lye is drastic, and if somebody has another working solution, I would be glad to hear it - I have an alu drip-catch pan in my oven which is covered in this gunk. – rumtscho Apr 8 '12 at 21:47
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    @rumtscho I've cleaned polymerized oil off with Bar Keeper's Friend. Not sure why your scouring pad didn't work, it should, as it actually removes metal. Unless you were using a non-scratch scouring pad... – derobert Apr 9 '12 at 17:38
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    @rumtscho: Bar Keeper's Friend is a polishing agent, or abrasive, not simply a chemical cleaner. It will remove the oil, AND leave a beautifully shiny, polished surface. Much better than the scratches from a scouring pad. – BobMcGee Apr 10 '12 at 13:30

I concur with rumtscho in that scraping isn't going to get this off. Before you go the route of lye, I would try one of two things:

1- Pour can of diced tomatoes into pan. Cook over medium heat until tomatoes start to bubble, stirring occasionally. Stir heavily once bubbling, then discard tomatoes and wash pan.

2- Fill pot with a large amount of rhubarb and water. Boil for a long time, adding water as necessary. Discard and wash.

  • I am guessing you believe the acids are going to dissolve the film? – Cos Callis Apr 7 '12 at 21:19
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    I have used the tomato technique effectively in the past and saw the rhubarb technique on an episode of "How clean is your house." – Jacob G Apr 8 '12 at 16:55
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    A modified version of this worked. I was able to get rid of most of the film by letting vinegar sit in the pan for a few hours, then boiling it and using a plastic scraper. – Mike Eng Apr 16 '12 at 2:38

OP also asked why this is happening. It's not absolute temperature; it's temperature relative to the smoke point if the oils you're cooking with. Let me guess -- extra virgin olive oil?

Try using higher smoke-point oils when you're saunteeing and doing high-temp things generally (peanut, sunflower, safflower, coconut, etc).

  • Yep, it was extra virgin olive oil. Thanks for the suggestion. I realized I just really don't need that much heat. – Mike Eng Feb 7 '14 at 20:27
  • That means the smoking point is the temperature, where the oil begins to polymerize? – erik Feb 22 '14 at 23:00

If the rest of the handle is also stainless steel you can put in your oven during a 'self-cleaning' cycle. The high heat should reduce that film to a charred residue to be cleaned off.

You might also try just pouring a can of Coca-Cola (not another cola drink) in the pan and let that sit over-night. The acid in Coke is strong enough to dissolve a nail, it will probably make short work of this.

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    Generally, bases are better at cleaning polymerized (and non-polymerized) oils than acids. An acid won't react with the oil, but it has a chance to dissolve the invisible oxide layer on the steel pot (below the oil). But forget the coca-cola urban legends; both vinegar and decalcifying tablets for kettles are a stronger acid than coca-cola, they have a higher chance of working. Oh, and the self-cleaning cycle is a very good idea; I just didn't think of it because my oven doesn't have it, but +1 for that. – rumtscho Apr 7 '12 at 21:37
  • I only postulated the Coke idea based on @Jacob G... The self-cleaning method was how we used to do those a restaurant I worked in (too many) years ago.. – Cos Callis Apr 7 '12 at 21:40

I have a D5 Brushed Stainless pan and I got a stain like this when I let my olive oil get too hot and it started smoking a bit. I tried soaking and it just didn't budge. I decided to try baking soda. Put about an inch of water in the pan and then add in baking soda, making a paste. Let this sit on the stain for 5-10 minutes. Then scrub. I use a cotton dish rag for scrubbing but a folded paper towel seems to do in a pinch. If that isn't strong enough add in some salt and scrub some more. It took about 30-45 minutes to clean the section of my pan that was stained. This pan will probably take over an hour of scrubbing to get clean. just keep working on it and you can get most of it off.


I have had this happen to me also. I have found that using Cameo has helped me.


I agree, Bar Keeper's Friend by far is the best. You will never need steel wool again. Also great for SS sinks. Then a quick wash to release the pwdr residue.

Before I found BKF, this optional method is only for Stainless Steel Sinks, I would the fill pot half way with water and ½ cup of DishWasher powder, Cascade if possible or use more with liquid. Bring to a boil and ventilate the kitchen. It will help release and burned food and oil enough so you can scrub it off. Also using a metal spatula helped to, but it will leave some scratches. But I was able to use the pot again. You need to weigh the options. You can also warm the pan under very hot water, then scrub with a paste made from the DW powder. Use gloves.

  • You really don't have to stop using the pan because of some polymerized oil. – Casey Jan 10 at 0:57

I've had success with SOS pads (Steel wool with embedded detergent). It's not easy, and it takes a while, but I can get my steel looking like new. You'll need to re-season it before use.


Forget the rubbing and scrubbing with Bar Keepers Friend or Cameo. This way is quick and easy. Heat the empty pan on medium heat for about 2-3 minutes. Take pan outside and spray with Easy Off oven cleaner (yellow cap not blue). When you spray the pan if the oven cleaner evaporates allow the pan to cool a few seconds and then continue spraying. What you want is the oven cleaner to foam up and stay on the pan. Allow the cleaner to stay on pan for 4-5 minutes and then rinse off with hot soapy water. Your pan will look like new. Do not use this method on aluminum pans.


ProTip: Try a Fabric Softener Sheet (really!). The ones you throw in your dryer. Fill pot / container with Hot water and add a sheet. Allow to soak overnight. Use plastic scrub brush and don't remove sheet as you're scrubbing - scrub with it (slightly abrasive).

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