Yixing Cleaning Advice

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MmBuddha
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Fri Dec 01, 2017 12:55 pm

Please let me know if this belongs in another section, but I thought I’d start a thread discussing ways to clean and restore old yixing pots before use.

I’ve heard a variety of techniques for cleaning, from milder sounding options like toothpaste and citric acid to denture cleaning tablets and bleach. Due to the nature of yixing I’d be reflexively wary of all of these but am aware they’re sometimes used even on valuable antique pots.

Any advice about the best methods you’ve found?
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Victoria
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Fri Dec 01, 2017 1:41 pm

Really depends on condition of clay, if it has a moldy smell, a lot of buildup and or black mold, or is pretty clean and just needs to be reset and christened. If the pot looks pretty good just soaking it for a day in water, and then pouring boiling water inside and outside might be good enough. Important to let pot dry completely after each use; I clean with boiling water, dry with soft cloth and let pot sit on sunny window sill for a few days to completely dry. For more problematic pots I wrote this guide a while ago; Awakening & Resetting Unglazed Ceramics/ Yixing from Discoloration, Staining & Mold
Last edited by Victoria on Wed Sep 05, 2018 6:54 pm, edited 1 time in total.
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MmBuddha
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Sat Dec 02, 2017 2:53 pm

Victoria wrote:
Fri Dec 01, 2017 1:41 pm
Really depends on condition of clay, if it has a moldy smell, a lot of buildup and or black mold, or is pretty clean and just needs to be reset and christened. If the pot looks pretty good just soaking it for a day in water, and then pouring boiling water inside and outside might be good enough. Important to let pot dry completely after each use; I clean with boiling water, dry with soft cloth and let pot sit on sunny window sill for a few days to completely dry. For more problematic pots I wrote this guide a while ago; Awakening & Resetting Unglazed Ceramics/ Yixing from Discoloration, Staining & Mold
Thanks Victoria, that sounds like great advice. It sounds like most well cared for teapots should be fine cleaned with soaking and boiling alone, and that Sodium percarbonate is a good solution for more seriously dirty/mouldy pots.

If you had a pot that didn’t appear mouldy, but had some stubborn tea stains, would you recommend using a bleach solution? If I ever tried something like that, I’d be judicious with rinsing, soaking and boiling to make sure no residue was left, but I think I’d feel wary of trying it. Do you find these more abrasive chemicals wash out effectively, without leaving any ill effects behind? Apologies if this is a jumble of questions.
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debunix
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Sat Dec 02, 2017 7:02 pm

I've reset cast iron with a self-cleaning oven cycle....why not a teapot?
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Victoria
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Sat Dec 02, 2017 8:58 pm

debunix wrote:
Sat Dec 02, 2017 7:02 pm
I've reset cast iron with a self-cleaning oven cycle....why not a teapot?
Is that just using heat, i.e. no chemicals? I wonder if stove gradually increases heat, seems it would right. Interesting experiment, slowly increasing heat, slowly decreasing heat to clean pot. I wouldn’t try on very old or very thin pots though :)
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debunix
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Sat Dec 02, 2017 9:33 pm

Yes, it's just using the self-cleaning cycle to heat it in the oven to about 700 degrees for long enough to basically vaporize any organic buildup on oven surfaces, and I presume in the pots as well, and then cooling back down. It should be pretty gentle for the pot, because the oven only heats up so fast, and it is locked when the cycle is going, so you can't open the door and drop the heat suddenly. So it should be pretty safe. But I still haven't been brave enough to prove that it works with a perfectly functional pot, and none of my pots have gotten funky enough to need more than a little baking soda (after forgetting with damp leaves inside over a weekend in the office....)
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tealifehk
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Sun Dec 03, 2017 7:17 am

MmBuddha wrote:
Sat Dec 02, 2017 2:53 pm
Victoria wrote:
Fri Dec 01, 2017 1:41 pm
Really depends on condition of clay, if it has a moldy smell, a lot of buildup and or black mold, or is pretty clean and just needs to be reset and christened. If the pot looks pretty good just soaking it for a day in water, and then pouring boiling water inside and outside might be good enough. Important to let pot dry completely after each use; I clean with boiling water, dry with soft cloth and let pot sit on sunny window sill for a few days to completely dry. For more problematic pots I wrote this guide a while ago; Awakening & Resetting Unglazed Ceramics/ Yixing from Discoloration, Staining & Mold
Thanks Victoria, that sounds like great advice. It sounds like most well cared for teapots should be fine cleaned with soaking and boiling alone, and that Sodium percarbonate is a good solution for more seriously dirty/mouldy pots.

If you had a pot that didn’t appear mouldy, but had some stubborn tea stains, would you recommend using a bleach solution? If I ever tried something like that, I’d be judicious with rinsing, soaking and boiling to make sure no residue was left, but I think I’d feel wary of trying it. Do you find these more abrasive chemicals wash out effectively, without leaving any ill effects behind? Apologies if this is a jumble of questions.
I just used bleach on two pots while waiting for sodium percarbonate to come in from China. I've used bleach many times and it has worked amazingly well to clean pots up, but apparently sodium percarbonate goes deeper and cleans everything. Sodium percarbonate is a really innocuous compound once it hits the water and is basically hydrogen peroxide. I'd go ahead and use sodium percarbonate. Bleach will get all the tea stains off but apparently won't get the mold out.

With bleach I make tea in the pot a few times after airing the pot out for several days and then use as normal. Bleach removed stains from pots that I couldn't remove with any other method! I haven't tried the sodium percarb yet so I can't comment on how well it works, but Victoria has and her results were astounding!
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MmBuddha
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Sun Dec 03, 2017 7:45 am

tealifehk wrote:
Sun Dec 03, 2017 7:17 am
MmBuddha wrote:
Sat Dec 02, 2017 2:53 pm
Victoria wrote:
Fri Dec 01, 2017 1:41 pm
Really depends on condition of clay, if it has a moldy smell, a lot of buildup and or black mold, or is pretty clean and just needs to be reset and christened. If the pot looks pretty good just soaking it for a day in water, and then pouring boiling water inside and outside might be good enough. Important to let pot dry completely after each use; I clean with boiling water, dry with soft cloth and let pot sit on sunny window sill for a few days to completely dry. For more problematic pots I wrote this guide a while ago; Awakening & Resetting Unglazed Ceramics/ Yixing from Discoloration, Staining & Mold
Thanks Victoria, that sounds like great advice. It sounds like most well cared for teapots should be fine cleaned with soaking and boiling alone, and that Sodium percarbonate is a good solution for more seriously dirty/mouldy pots.

If you had a pot that didn’t appear mouldy, but had some stubborn tea stains, would you recommend using a bleach solution? If I ever tried something like that, I’d be judicious with rinsing, soaking and boiling to make sure no residue was left, but I think I’d feel wary of trying it. Do you find these more abrasive chemicals wash out effectively, without leaving any ill effects behind? Apologies if this is a jumble of questions.
I just used bleach on two pots while waiting for sodium percarbonate to come in from China. I've used bleach many times and it has worked amazingly well to clean pots up, but apparently sodium percarbonate goes deeper and cleans everything. Sodium percarbonate is a really innocuous compound once it hits the water and is basically hydrogen peroxide. I'd go ahead and use sodium percarbonate. Bleach will get all the tea stains off but apparently won't get the mold out.

With bleach I make tea in the pot a few times after airing the pot out for several days and then use as normal. Bleach removed stains from pots that I couldn't remove with any other method! I haven't tried the sodium percarb yet so I can't comment on how well it works, but Victoria has and her results were astounding!
Good to hear you’ve had success using a similar approach. I’d have thought the most important thing is how readily any chemical used will wash out, leaving as little trace behind as possible. I heard Marshaln recommend bleach a long time ago, but thought it sounded crazy at the time. Besides bleach (Sodium hypochlorite), I’ve heard both Hydrogen peroxide and now Sodium percarbonate recommended (thanks to Victoria and yourself). Someone on Teachat mentioned that Hydrogen Peroxide decomposes into oxygen and water naturally, and someone told me that bleach reduces to salt.

I’m no chemist (you don’t say), so is there any way to differentiate the effects of these chemicals for this sort of thing, and work out which might be the safest bet in terms of leaving yixing clay unbothered after the cleaning is done?

P.S. if anyone has tried using an ultrasonic cleaner I’d be very interested to hear how it went. Small capacity cleaners designed for jewellery etc. are actually pretty cheap and widely available, and I certainly like the idea of cleaning without chemicals, but no idea if it could handle stains inside the pot.
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tealifehk
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Sun Dec 03, 2017 9:13 am

I have an ultrasonic cleaner specifically for teapots. I used it to clean a Chaozhou pot that had been painted black, inside and out! I have no idea why. Lots of alcohol and ultrasonic cleaning removed almost all of the paint, but I am still not planning on using the pot. I got a full refund for it anyway as the vendor had never said it had been filled with paint :o

I've used the cleaner for other pots; soapy water or whatever won't do anything. Bleach is pretty innocuous and I've noticed absolutely no ill effects on the clay from using it. Sodium percarb...I'll let you know! I am going to use it sparingly as I've heard the pure stuff can damage glass.
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Victoria
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Sun Dec 03, 2017 2:49 pm

tealifehk wrote:
Sun Dec 03, 2017 9:13 am
I have an ultrasonic cleaner specifically for teapots. I used it to clean a Chaozhou pot that had been painted black, inside and out! I have no idea why. Lots of alcohol and ultrasonic cleaning removed almost all of the paint, but I am still not planning on using the pot. I got a full refund for it anyway as the vendor had never said it had been filled with paint :o

I've used the cleaner for other pots; soapy water or whatever won't do anything. Bleach is pretty innocuous and I've noticed absolutely no ill effects on the clay from using it. Sodium percarb...I'll let you know! I am going to use it sparingly as I've heard the pure stuff can damage glass.
Yeah, I’d say you need at least 1 tablespoon Percarbonate inside and another tablespoon for outside of pot. At least that is what worked for me with my large red clay 750ml kettle. I guess you can proportion down, but need to let it soak a while, till it’s cooled down.
ChaLover
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Tue Dec 12, 2017 12:18 pm

So I have used what I understand to be pure powdered Hydrogen Peroxide for years to clean all sorts of stained vitrious tea ware - glass and glazed items. I used once on a musty old clay tea pot. For me it has done a super job at getting the tea stains and oils off tea wares - with no scrubbing.

I believe it's sold under the name Oxi-clean and Oxi-brite (different companies). Whole Foods sells the Oxi-brite. But only use the versions with the pure white powder and no detergent additives, definitely not the kind with the colored detergent crystals.

Just add filtered hot water to a small scoop in a container deep enough to submerge items and let item soak over night. Then rinse super well with filtered clean hot water until all residue gone. Usually take just a few rinses. Then let dry. Hope this helps!
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pedant
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Tue Dec 12, 2017 2:17 pm

the mechanism of stain removal using oxidizers like peroxide, percarbonate, and bleach is more about modification than removal.
oxidizers degrade chromophores (conjugated parts of molecules causing color) rendering them no longer colorful or sometimes just changing their color.
if it's all about aesthetics, then it doesn't matter.
however, some food for thought:
  • that modified stain residue is still there. does that matter?
  • many people believe that the surface of many tea vessels (e.g. zisha) contains reactive species that have some desirable effect on the flavor of tea.
    how do you know for sure that oxidizers aren't reacting with exposed bits of metal particles and oxidizing them? isn't it possible that this could be subtley changing a pot's characteristics?
i personally favor removing tea stains mechanically by scrubbing with baking soda paste. that's how i reset pots. it's not that much effort and works well IME.
for porcelain cups or whatever, melamine foam (e.g. 'magic eraser' sponge brand name) is a similar thing to try.
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tealifehk
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Thu Sep 06, 2018 3:39 pm

So there's been a fair bit of attention around this thread today: I want to add that I've since tried ethanol, isopropyl alcohol, hydrogen peroxide and sodium perchlorite. Bleach works the best, hands down. The other solvents will have varying degrees of utility. Ethanol and isopropyl will remove certain types of ink and paint that may be on a pot, for example. H2O2 and sodium perchlorite were not as effective for me, but they do work to some extent. Bleach works instantly on tea stains and many other types of residue!
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