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Re: Awakening & Resetting Unglazed Ceramics / Yixing from Storage, Discoloration, Staining & Mold

Posted: Wed Jan 23, 2019 8:27 am
by Chip
An interesting reread! Obviously a lot of thought and experimentation has gone into this process. Thank you for sharing all this info along with individual cases.

Not saying that I would personally go this route, but I can see potential benefits.

Re: Awakening & Resetting Unglazed Ceramics / Yixing from Storage, Discoloration, Staining & Mold

Posted: Fri Apr 19, 2019 1:09 pm
by Victoria
I’m adding these useful brushes for cleaning hard to get to places like spouts, filters, inside kyusu handles, katakuchi and cups. The brushes with cotton ball tips are useful to safely clean fine porcelain cups, in that less pressure is needed to clean so preventing possible breakage.


Cleaning Brushes: Nylon Tube Brushes
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Bottle Cleaning Brush Set: Long Handle Bottle Cleaner for Washing Narrow Wine/Beer Bottles
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Bottle Brush Cleaner: Long Water Bottle and Straw Cleaning Brush
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862F8E03-0628-4E58-9495-1F0FA5ED30ED.jpeg (16.81 KiB) Viewed 11984 times

Microfiber Tip Brushes: Soft Tip Brushes
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CB9FB451-85A3-4FF7-B456-0B547545A37B.jpeg (12.67 KiB) Viewed 11979 times

Re: Awakening & Resetting Unglazed Ceramics / Yixing from Storage, Discoloration, Staining & Mold

Posted: Sun Apr 21, 2019 3:47 am
by braden87
Thanks so much Victoria. I used your sodium percarbonate method to rescue three pots (one very old, one 80s and one 90s) that were in a very bad state. It worked perfectly, I'm so pleased. So no more odor, they look brand new. I wish I could have kept the aged look on the significantly old one, but it was unusable due to the funk inside. Cheers!

Re: Awakening & Resetting Unglazed Ceramics / Yixing from Storage, Discoloration, Staining & Mold

Posted: Sun Apr 21, 2019 5:59 am
by Bok
@braden87 yes this method is brilliant! I still can’t believe how brand new some really old and dirty pots can become. Sure old patina is nice, but I prefer to be the author of it, who knows what the previous owner did with it.

Very old pot? Care to share? I am sure a lot of us are curious :)

Re: Awakening & Resetting Unglazed Ceramics / Yixing from Storage, Discoloration, Staining & Mold

Posted: Wed Apr 24, 2019 12:22 pm
by braden87
Bok wrote:
Sun Apr 21, 2019 5:59 am
Very old pot? Care to share? I am sure a lot of us are curious :)
It's a sand mixed Zhu Ni beast (capacity is about 450ml). Previous owner indicated it's from the early R.O.C. or late Qing. I'm no expert, but comparison with other examples leads to believe this is true. I find the style used to shape the lid (especially the longer lip that goes into the teapot itself - very rounded and thick) is very distinct during that period. The state it came in definitely supports the theory that it has seen quite a few decades, it definitely wasn't shoe polish. Regardless of the age, I love it. The appliqué work is outstanding, and it has a poem written in calligraphy. It cleaned up really nicely, but the build up from age gave the appliqué a nice "shadow" (if you will) that's now gone :( If I get some downtime at home I'll try to remember to snap a pic and post here.

Re: Awakening & Resetting Unglazed Ceramics / Yixing from Storage, Discoloration, Staining & Mold

Posted: Wed Apr 24, 2019 1:20 pm
by Victoria
braden87 wrote:
Wed Apr 24, 2019 12:22 pm
..... The appliqué work is outstanding, and it has a poem written in calligraphy. It cleaned up really nicely, but the build up from age gave the appliqué a nice "shadow" (if you will) that's now gone :( If I get some downtime at home I'll try to remember to snap a pic and post here.
For this reason I have not yet cleaned my Jozan II with calligraphy using Percarbonate, and don’t rub too much another Hongni pot with calligraphy when drying. For the Jozan I may just use baking soda and white vinegar at some point. I wonder what potters use to darken and or lighten the grooves of the engraved calligraphy.

Glad that the instructional help you clean your pots [mention]braden87[/mention].

Re: Awakening & Resetting Unglazed Ceramics / Yixing from Storage, Discoloration, Staining & Mold

Posted: Wed Apr 24, 2019 6:51 pm
by Bok
braden87 wrote:
Wed Apr 24, 2019 12:22 pm
Bok wrote:
Sun Apr 21, 2019 5:59 am
Very old pot? Care to share? I am sure a lot of us are curious :)
It's a sand mixed Zhu Ni beast (capacity is about 450ml). Previous owner indicated it's from the early R.O.C. or late Qing. I'm no expert, but comparison with other examples leads to believe this is true. I find the style used to shape the lid (especially the longer lip that goes into the teapot itself - very rounded and thick) is very distinct during that period. The state it came in definitely supports the theory that it has seen quite a few decades, it definitely wasn't shoe polish. Regardless of the age, I love it. The appliqué work is outstanding, and it has a poem written in calligraphy. It cleaned up really nicely, but the build up from age gave the appliqué a nice "shadow" (if you will) that's now gone :( If I get some downtime at home I'll try to remember to snap a pic and post here.
Please do! Such large pots in Zhuni are rather unusual, it is very difficult to fire this clay at such a size without destroying them, especially back in the old days. If you take images please snap one of the insides as well! That and that it has carvings would make me highly suspicious of it being an antique Zhuni.

Well, if you did not pay a couple of 1000$ for it, it probably isn’t :)

How to clean off lime scale?

Posted: Thu Jul 18, 2019 10:05 am
by Bok
Got a new tiny old pot for a Kintsugi project. It has some heavy lime scale and I am looking into ways to get rid of it, without rendering the pot unusable...

The usual baking soda, sodium percarbonate method does not work for lime scale.

I have heard people mention house hold vinegar or citric acid, but I am not sure if that would affect the clay negatively.

The clay in question is Hongni.

Good ideas anyone?

Re: How to clean off lime scale?

Posted: Thu Jul 18, 2019 10:32 am
by Victoria
Hi Bok, white vinegar (distilled vinegar) will not hurt your pot, it evaporates. It should help with lime deposits. I’d soak it for a few hours in a 50/50 solution of white vinegar and filtered water, then give it a good scrub with a non abrasive brush. Let us know how it goes.

p.s. After vinegar soak, if lime is still stubborn, try rubbing with baking soda and vinegar together. But remember, when using baking soda always follow with a 50/50 white vinegar wash, to balance PH, and remove any residual baking soda. Follow with a few very hot water washes.

Re: How to clean off lime scale?

Posted: Thu Jul 18, 2019 10:40 am
by Bok
Victoria wrote:
Thu Jul 18, 2019 10:32 am
Let us know how it goes.
Cheers Victoria, I will try and report back!

Re: Cleaning: Awakening & Resetting Unglazed Ceramics / Yixing

Posted: Sun Jul 21, 2019 8:07 pm
by Dresden
Another good option to remove scale (as well as stains from porcelain) is citric acid and baking soda. In fact, citric acid is what zojirushi recommends when cleaning scale from their water boilers.

Re: Cleaning: Awakening & Resetting Unglazed Ceramics / Yixing

Posted: Sun Jul 21, 2019 8:19 pm
by Victoria
Dresden wrote:
Sun Jul 21, 2019 8:07 pm
Another good option to remove scale (as well as stains from porcelain) is citric acid and baking soda. In fact, citric acid is what zojirushi recommends when cleaning scale from their water boilers.
Good idea. Do you use citric acid for anything else?

Re: Cleaning: Awakening & Resetting Unglazed Ceramics / Yixing

Posted: Sun Jul 21, 2019 8:23 pm
by Dresden
Victoria wrote:
Sun Jul 21, 2019 8:19 pm
Good idea. Do you use citric acid for anything else?
The only other time I have used citric acid is canning tomatoes.

Re: Cleaning: Awakening & Resetting Unglazed Ceramics / Yixing

Posted: Sun Jul 21, 2019 8:31 pm
by Victoria
Dresden wrote:
Sun Jul 21, 2019 8:23 pm
Victoria wrote:
Sun Jul 21, 2019 8:19 pm
Good idea. Do you use citric acid for anything else?
The only other time I have used citric acid is canning tomatoes.
Wondering now, does it leave any sour-tasting notes behind, or do those evaporate like with vinegar?

Re: Cleaning: Awakening & Resetting Unglazed Ceramics / Yixing

Posted: Sun Jul 21, 2019 8:37 pm
by Dresden
Victoria wrote:
Sun Jul 21, 2019 8:31 pm
Dresden wrote:
Sun Jul 21, 2019 8:23 pm
Victoria wrote:
Sun Jul 21, 2019 8:19 pm
Good idea. Do you use citric acid for anything else?
The only other time I have used citric acid is canning tomatoes.
Wondering now, does it leave any sour-tasting notes behind, or do those evaporate like with vinegar?
Good question. I've not used it on anything super porous. When canning it does not add any particular flavor but does add tartness. I would definitely test it before using it on anything I would consider valuable.