Cleaning: Awakening & Resetting Unglazed Ceramics / Yixing

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Bok
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Mon Mar 16, 2020 10:09 am

Youzi wrote:
Mon Mar 16, 2020 9:24 am
Has anyone tried cooking a pot in lemon juice/ critic acid / in an acidic substance, or soak it in an acidic water for a long time?
Actually doing that at this moment... not cooking though, just put hot water, pot and citric acid together and let it sit.

Only way to get rid of some tenacious lime scale.
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pantry
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Mon Mar 16, 2020 10:31 am

Bok wrote:
Mon Mar 16, 2020 10:09 am
Youzi wrote:
Mon Mar 16, 2020 9:24 am
Has anyone tried cooking a pot in lemon juice/ critic acid / in an acidic substance, or soak it in an acidic water for a long time?
Actually doing that at this moment... not cooking though, just put hot water, pot and citric acid together and let it sit.

Only way to get rid of some tenacious lime scale.
Similarly, but I just rubbed the spots with a slice of lime/lemon
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Victoria
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Mon Mar 16, 2020 3:10 pm

Bok wrote:
Mon Mar 16, 2020 10:09 am
Youzi wrote:
Mon Mar 16, 2020 9:24 am
Has anyone tried cooking a pot in lemon juice/ critic acid / in an acidic substance, or soak it in an acidic water for a long time?
Actually doing that at this moment... not cooking though, just put hot water, pot and citric acid together and let it sit.
Only way to get rid of some tenacious lime scale.
Interesting, Let us know how this goes in comparison to percarbonate soak.
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Bok
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Mon Mar 16, 2020 7:48 pm

Victoria wrote:
Mon Mar 16, 2020 3:10 pm
Bok wrote:
Mon Mar 16, 2020 10:09 am
Youzi wrote:
Mon Mar 16, 2020 9:24 am
Has anyone tried cooking a pot in lemon juice/ critic acid / in an acidic substance, or soak it in an acidic water for a long time?
Actually doing that at this moment... not cooking though, just put hot water, pot and citric acid together and let it sit.
Only way to get rid of some tenacious lime scale.
Interesting, Let us know how this goes in comparison to percarbonate soak.
It’s not a replacement, I only do this when there is white lime scale. For that it needs a few rounds to work.
Mark-S
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Thu May 21, 2020 2:28 pm

I soak my pots in filtered water before boiling them. With some pots I have noticed that they get very slippery/soapy/slimy in the water. For some reason, this does not happen with all pots. What could be the cause of that? Tea oil? Additives? ...? Has anyone experienced the same?
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Victoria
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Thu May 21, 2020 4:38 pm

Mark-S wrote:
Thu May 21, 2020 2:28 pm
I soak my pots in filtered water before boiling them. With some pots I have noticed that they get very slippery/soapy/slimy in the water. For some reason, this does not happen with all pots. What could be the cause of that? Tea oil? Additives? ...? Has anyone experienced the same?
If they are Chinese pots, wax might have been applied on the outside to look shinny. If they are pots you’ve been using for a long time, then it could be accumulated fatty acids from teas brewed. Cleaning your pots with boiling water after each use helps to prevent this build up. Hope your just simmering (not boiling) your teapots, with cloth protection so they don’t rattle and crack :) .
Mark-S
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Thu May 21, 2020 4:49 pm

Victoria wrote:
Thu May 21, 2020 4:38 pm
If they are Chinese pots, wax might have been applied on the outside to look shinny. If they are pots you’ve been using for a long time, then it could be accumulated fatty acids from teas brewed. Cleaning your pots with boiling water after each use helps to prevent this build up. Hope your just simmering (not boiling) your teapots, with cloth protection so they don’t rattle and crack :) .
Yes, they are Yixing pots. What's kind of weird is that they are not very shiny, but I also don't think that they were used that often. :? Is there any way I could test if they got wax applied to the outside? And is there another explanation for this?
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Victoria
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Thu May 21, 2020 5:28 pm

Mark-S wrote:
Thu May 21, 2020 4:49 pm
Victoria wrote:
Thu May 21, 2020 4:38 pm
If they are Chinese pots, wax might have been applied on the outside to look shinny. If they are pots you’ve been using for a long time, then it could be accumulated fatty acids from teas brewed. Cleaning your pots with boiling water after each use helps to prevent this build up. Hope your just simmering (not boiling) your teapots, with cloth protection so they don’t rattle and crack :) .
Yes, they are Yixing pots. What's kind of weird is that they are not very shiny, but I also don't think that they were used that often. :? Is there any way I could test if they got wax applied to the outside? And is there another explanation for this?
Other than applied polish/wax and or frequent use without cleaning, I can’t think of another reason for slippery/soapy/slimy build-up in water. I’d just simmer several times with filtered water and protective cloth. If you still get residual build-up in water, then I’d go to step C., and if it’s still an issue then step D.;
Victoria wrote:
Wed Sep 05, 2018 6:45 pm
Awakening & Resetting Unglazed Ceramics / Yixing from Storage, Discoloration, Staining, Lime & Mold

C. Getting Rid of Discoloration in Yixing (if pot is still dirty, moldy or smelly then try the following)
1. Lightly scrub with Baking Soda, using non abrasive material so as not to scratch clay.
If pot is still not clean then;
2. Follow steps 1-4 in B. Resetting Old Yixing, and repeat these steps adding 3 TBS Baking Soda. Simmer for 1hr. After pot is somewhat cooled lightly scrub pot again, using non abrasive material so as not to scratch clay. Follow with a white vinegar bath (to fully remove traces of baking soda) by soaking it in hot dilute vinegar for about an hour before giving it a final soak in hot water. All traces of vinegar will evaporate within 24-48hrs.

D. Use Sodium Percarbonate if Discoloration & or Mold remains (If pot is still not clean)
Mark-S
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Thu May 21, 2020 5:43 pm

@Victoria

Okay, thanks. I think if they applied polish/wax to it there should be a visible change to the pot after cleaning it. I'll take comparison photos in the future. Maybe, I can figure out this way what's going on there.
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debunix
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Fri May 22, 2020 11:17 am

Where do you store your sodium percarbonate? I just bought a bottle to try working with a few stained pieces, and I was surprised to see the label states that it not only is it flammable, but it can intensify fires. It probably needs to live outside, but even the corners of my concrete patios have wood fence above them.
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Bok
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Fri May 22, 2020 11:20 am

debunix wrote:
Fri May 22, 2020 11:17 am
Where do you store your sodium percarbonate? I just bought a bottle to try working with a few stained pieces, and I was surprised to see the label states that it not only is it flammable, but it can intensify fires. It probably needs to live outside, but even the corners of my concrete patios have wood fence above them.
Mine came in a plain plastic bag :/ No warning signs or anything. I have it in a jar in the kitchen, which reading this, is probably not a good idea
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debunix
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Fri May 22, 2020 11:39 am

I just put mine out on the patio. I'll figure out a better spot later. Maybe I can tape it to the underside of my concrete patio table :D

It has a rather intimidating safety data sheet.

"SECTION 7: Handling and storage
7.1 Precautions for safe handling
Avoid contact with skin and eyes. Avoid formation of dust and aerosols.
Provide appropriate exhaust ventilation at places where dust is formed.Keep away from sources of ignition - No smoking.Keep away from heat and sources of ignition.Normal measures for preventive fire protection.
For precautions see section 2.2.
7.2 Conditions for safe storage, including any incompatibilities
Keep container tightly closed in a dry and well-ventilated place. Storage class (TRGS 510): 5.1B: Oxidizing hazardous materials
7.3 Specific end use(s)
Apart from the uses mentioned in section 1.2 no other specific uses are stipulated"
Mark-S
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Fri May 22, 2020 12:33 pm

debunix wrote:
Fri May 22, 2020 11:17 am
Where do you store your sodium percarbonate?
For now, I store it inside my apartment at a dry place in a paper bag with an additional plastic bag around it. A container would be better suited, but I was too lazy to buy one.
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Victoria
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Fri May 22, 2020 12:45 pm

Mark-S wrote:
Fri May 22, 2020 12:33 pm
debunix wrote:
Fri May 22, 2020 11:17 am
Where do you store your sodium percarbonate?
For now, I store it inside my apartment at a dry place in a paper bag with an additional plastic bag around it. A container would be better suited, but I was too lazy to buy one.
I always use it outside, and store it in its plastic container sealed in an exterior cabinet. I should add this information at the beginning of this thread. If anyone has additional recommendations that you think I should add let me know.
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debunix
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Fri May 22, 2020 11:01 pm

Wow. It really works. I have to wait for morning light to get the after photos on two pots I used it on today. It was so effective on what were really just tea stains--no scary funky stuff--that I skipped the boiling steps.

[EDIT:
I have to backtrack a little on this part: after they dried, some white stains appeared, so there was some scum or deposit that was simply invisible when they were wet. Just set them up to boil, will report back later, but wanted to make this correction.]

[Still] Very impressed. I'll stick to baking soda as my go-to when it's time to do something more than a quick rinse & wipe, because it's so easy to use. But for longer-term deep stains that are just plain ugly, on unglazed interiors, wow. And it seems like it ought to be a lot gentler than soda scrubs--because really baking soda is all about the elbow grease--for delicate glazes. For future reference, is there any reason to worry about delicate crackled and snow-flake style glazes with percarbonate? I'm thinking specifically of the shell imprint in the bottom of the Flower of Forgetfulness....

Image

...could it loosen the flakes?

Image

I'm guessing it would not penetrate enough to really alter the crackle staining.
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