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Anyone has experience cleaning burn marks on a non-glazed ceramic kettle? I picked up this kettle recently, and it seems it was heavily used. The black area looks like burn mark, and I have no idea what's the white spots. The white spots reminded me of decay on the inner base of a tetsubin.

i'm sure there will be differing opinions on this...

interesting. those spots look purple on my monitor. looks like petri culture. rad.

how wide is the lid opening of the kettle? that's on the inside, right? wondering how much room you have to work.

i wonder why the residue is so dark. could something other than water have been used in it? even if it ran dry, i'd expect white residue. imo that dark color suggests organic material in the residue. trace amounts from whatever was in the water (a natural water source perhaps?) that got incorporated into the mineral scale as it formed and then decomposed and turned dark when it got dry heated?

i'd treat it like mineral scale and hope most of it comes out. e.g. you can try filling the kettle with 1:1 distilled vinegar and water (resulting in 2.5% "acidity"). you can even gently simmer that if you want. then rinse it out and give it a good scrub.

then re-evaluate after.

@pedant
The kettle is about 600-750 ml. Opening rim is about 4 inches wide.
It has been soak in tap water today. I’ll use vinegar tomorrow. And maybe sodium percarbonate afterward. I hope the white spots are minerals. I’ll post a more pictures after vinegar treatment.

My guess is that the previous owner tried a rice (water) seasoning of the kettle ...and the rice got burnt.
I'd try a long soak in sodium percarbonate and some scrubbing (perhaps even with a kitchen steel scouring ball if needed).
EDIT: On a second thought the steel could enter into the ceramic surface as it abrades against it and might be hard to clean afterwards, so maybe no scrubbing with steel.

I put that baby in the oven on self cleaning cycle. Just carbonized whatever made those disturbing purple spots. Then percarbonate soaks and scrubbing.

After soaking, I checked the whole pot in detail. It looks like the white spot maybe the base clay. I used a sodium Percarbonate to clean the inside. Here are a few photos of the surface wear on the rim and the base. I did not expect the base clay to be this color lol

.m. wrote: ↑

Sat Aug 07, 2021 9:23 pm

My guess is that the previous owner tried a rice (water) seasoning of the kettle ...and the rice got burnt.

oh yeah. that's almost certainly what it was.

debunix wrote: ↑

Sun Aug 08, 2021 10:07 am

I put that baby in the oven on self cleaning cycle.

i like this idea

DailyTX wrote: ↑

Sun Aug 08, 2021 11:51 am

After soaking, I checked the whole pot in detail. It looks like the white spot maybe the base clay. I used a sodium Percarbonate to clean the inside. Here are a few photos of the surface wear on the rim and the base. I did not expect the base clay to be this color lol

Wow, that is a surprising outcome! Well, it is mass produced stuff after all...

Bok wrote: ↑

Sun Aug 08, 2021 8:02 pm

DailyTX wrote: ↑

Sun Aug 08, 2021 11:51 am

After soaking, I checked the whole pot in detail. It looks like the white spot maybe the base clay. I used a sodium Percarbonate to clean the inside. Here are a few photos of the surface wear on the rim and the base. I did not expect the base clay to be this color lol

Wow, that is a surprising outcome! Well, it is mass produced stuff after all...

@Bok
Yeah…I would never thought of the white spots are inner clay. Since this kettle is semi porous, do you think it’s safe to continue using it?

DailyTX wrote: ↑

Sun Aug 08, 2021 11:46 pm

Since this kettle is semi porous, do you think it’s safe to continue using it?

I have no idea, but I imagine modern pottery would need to go through some process of food safety standards.

Bok wrote: ↑

Mon Aug 09, 2021 1:28 am

DailyTX wrote: ↑

Sun Aug 08, 2021 11:46 pm

Since this kettle is semi porous, do you think it’s safe to continue using it?

I have no idea, but I imagine modern pottery would need to go through some process of food safety standards.

@Bok
I’ll give this kettle a try just for the record I tried Lin’s ceramic kettle haha, and hope I don’t

i think it's fine to use.

Here is the end result of the cleaning. The pot is back to soaking, and I'll do 2 boils later tonight. The burn marks are mostly gone.

@DailyTX - I am glad this worked out well.

I agree with the above comments and would add an alternative approach for anyone with the same predicament: walnut powder with a wet Magic Eraser is a safe abrasive to use.

It does take some scrubbing but has worked miracles for me with lime scale on Tokoname bonsai pots.

Cheers!

Baisao wrote: ↑

Sun Aug 15, 2021 3:41 pm

DailyTX - I am glad this worked out well.

I agree with the above comments and would add an alternative approach for anyone with the same predicament: walnut powder with a wet Magic Eraser is a safe abrasive to use.

It does take some scrubbing but has worked miracles for me with lime scale on Tokoname bonsai pots.

Cheers!

@Baisao
Thanks for the recommendation, I’ll try to get some walnut powder to try it next time. For this kettle, sodium percarbonate did most of the work.