Stubborn Rust Residue

[John Natoli]

I have a 12 lodge I bought new and use fairly often. I recently received 4 pieces from my wifes mother who kept her grandfathers cast iron skillets in the attic for decades. 1 is a Wagnerware Sidney -0- Bacon and Egg Skillet 1101E...another is a Griswold No 8 with 704U on the bottom as well...there are 2 other very small skillets ( like to cook an egg) ones a 3 notch lodge and the other a good health. My issue is getting the rust off....I received them in bad condition but after a series of cleanings they now look fairly good , just not good enough to cook in. The issue is residual rust. theres a light coating of rust that even after 3 series of cleaning in a self cleaning mode in the oven and a 12 hr vinegar bath and scrubbed with 000 pads the stains wont come out. even when I dry then they stain my towels with some grey matter... what can I do...the 2 small skillets are currently getting a cleaning with heavy duty oven cleaner....advice?

 

[Doug D.]

The SCO is not really meant to deal with rust. Bare clean iron will begin to "flash rust" almost immediately upon contact with air. The black residue you're getting is another form of oxide resulting from either the high temp of the SCO or the vinegar. Oven cleaner spray is also ineffective on rust. Flash rust and black oxide will both come off with the excess oil being wiped off when doing the initial seasoning.

See also: http://www.castironcollector.com/restore.php

 

[Jeff S.]

No additional advice to offer on your stains but I do have a recommendation on your cleaning process. If your set on using a vinegar bath for rust removal I would cut WAY back on your soak time. Too long of a soak is a surefire way to ruin a good piece of cast iron.

 

[D_Madden]

depending on what you've done in the cleaning process there always seems to be more 'residue' than what you expect.. I know I've worked on pieces, pulled them out of the e-tank, wipe dry, rub with steel wool... rinse, dry, more steel wool, rinse, dry... and I think they're pretty clean... but then I go to the kitchen to wash and dry them before seasoning and am just amazed at how much grey/black residue still comes off... usually I just keep rinsing (cold water) and wiping with paper towels until they stop staining the paper towels too much... then dry in the oven and start the seasoning process... sometimes there is a little more residue when wiping on that first coat of oil...

 

[John Natoli]

The SCO is not really meant to deal with rust. Bare clean iron will begin to "flash rust" almost immediately upon contact with air. The black residue you're getting is another form of oxide resulting from either the high temp of the SCO or the vinegar. Oven cleaner spray is also ineffective on rust. Flash rust and black oxide will both come off with the excess oil being wiped off when doing the initial seasoning.

See also: http://www.castironcollector.com/restore.php

So youre saying scrub it out..dry it and start seasoning process even with the "residue" still on it and it will come off during the seasoning process?

 

[Ty L.]

So youre saying scrub it out..dry it and start seasoning process even with the "residue" still on it and it will come off during the seasoning process?

That's what he's saying. Most of the flash rust and black oxide will end up on the rag you use to season the pan with. For the first coat I'll often apply the oil, then wipe off as much as I can with a paper towel, then add a little more oil, and again remove as much as I can with a paper towel. Then I attempt to "dry it off" with an old cotton t-shirt turned into a rag. Even after that there's usually a little residue but I don't worry about it. I bake it and the pan comes out just fine.

 

[John Natoli]

That's what he's saying. Most of the flash rust and black oxide will end up on the rag you use to season the pan with. For the first coat I'll often apply the oil, then wipe off as much as I can with a paper towel, then add a little more oil, and again remove as much as I can with a paper towel. Then I attempt to "dry it off" with an old cotton t-shirt turned into a rag. Even after that there's usually a little residue but I don't worry about it. I bake it and the pan comes out just fine.

GREAT! I'll try that..THANKS!

 

[Jeff S.]

...pulled them out of the e-tank, wipe dry, rub with steel wool... rinse, dry, more steel wool, rinse, dry...

D_Madden, am I reading your post correct in that you dry your iron before scrubbing with steel wool? Although I've never tried it that way I believe you get better results keeping everything wet when scrubbing.