Another Cast Iron Cleaning Issue.
After 30 years careful ownership of my favourite LC, I took my eye off the ball and burnt some braised red cabbage I was reheating. The accompanying photo shows it after a boil up, scrape, and 6 hour soak with undiluted white vinegar, which has had no effect whatsoever. I'll try the same with baking powder next and report back (next weekend, as I'm not at this house during the week).
I partially blame my new and useless glass cooktop.
All suggestions welcome.
1. warm pot-spray with oven cleaner-leave on a couple of minutes-scrub with green scrubbie-rinse well with hot water-repeat. DON'T LEAVE ON VERY LONG > IT COULD EASILY ETCH
2. barkeepers friend with tiny bit of water and soft sponge, massage gently-rinse well-repeat.
3. fill pot 3/4 full of water-add 2 tsp bleach-boil-let cool-dump out liquid BUT SAVE-green scrubbie again-rinse well with hot water-put liquid back in-boil-cool-repeat
I've gotten desperate and used Babbo in a frenzy with lots of elbow grease and scrubbed until my arm fell off. but buyer beware, that does etch and ruin the inside surface.
after it all comes off and I'm confident it will- rinse in warm water-dry well with soft cloth and continue enjoying your pot.
You can give baking soda a try if you like. Put the baking soda and water in. Bring it up to a boil, and let's it sit for an hour or two. Vinegar is mildly acidic, and baking soda is mildly basic. Baking powder is more neutral. So no need to try baking powder.
Bar Keeper's Friend is a fine alternative to vinegar, and should be stronger.
Diluted household ammonia is a stronger choice than baking soda solution, but do NOT heat up ammonia. Diluted bleach is also a alternative. Oven cleaner as well. Do NOT heat up these three.
Ammonia, bleach and oven cleaner will most certainly work, but they are also much more aggressive and they may etch the surface.
My first instinct would be to soak the spot in a paste of water and Barkeeper's Friend. You hardly need any water, just enough to cover the spot completely with the paste.
If you see black peeking through, add a little more BKF.
I'd leave this paste on for an hour, then scrub with a Dobie pad. If you see that this is working, but it's not completely clean, rinse and repeat, waiting another hour, or longer.
If this doesn't work, come back and try another solution.