Cleaning: Awakening & Resetting Unglazed Ceramics / Yixing

[Ackernym]

Time is precious, vinegar is stinky and boiling is risky. I'd go straight to percarbonate
[/quote]

Thanks! Yeah I'll definitely keep that in mind the next time I need to clean out any of my clay teapots, because cleaning my pot this time took SEVERAL HOURS

[faj]

Time is precious

That is what I tell my kids all the time, but usually the life advice that follows is not about the use of percarbonate. And falls on deaf ears.

But yeah, percarbonate works great. With clay items, but also with glass items that get stained and cloudy.

[TeaTotaling]

Time is precious

That is what I tell my kids all the time, but usually the life advice that follows is not about the use of percarbonate. And falls on deaf ears.

But yeah, percarbonate works great. With clay items, but also with glass items that get stained and cloudy.

Do you know if percarbonate is porcelain safe? I'm wondering if it might have a corrosive affect on the glaze. I have some glazed wares that could use an effortless cleaning solution.

[Victoria]

Do you know if percarbonate is porcelain safe? I'm wondering if it might have a corrosive affect on the glaze. I have some glazed wares that could use an effortless cleaning solution.

For porcelain I recommend baking soda and vinegar mix, let it sit a while, very lightly rub, wash with water, followed by a white vinegar wash to balance Ph. A 50/50 mixture of bleach can be used also, letting it sit a while. Percarbonate is safe for porcelain, glass, clay, fabric, rugs… but a step up in terms of chemical reactivity. Sometimes the quickest solution is not the most prudent, if repeat applications are a given.

[Baisao]

Time is precious

That is what I tell my kids all the time, but usually the life advice that follows is not about the use of percarbonate. And falls on deaf ears.

But yeah, percarbonate works great. With clay items, but also with glass items that get stained and cloudy.

Do you know if percarbonate is porcelain safe? I'm wondering if it might have a corrosive affect on the glaze. I have some glazed wares that could use an effortless cleaning solution.

It’s absolutely porcelain safe. A soak in a little warm water with percarbonate and wipe with a Magic Eraser and you’re good.

[TeaTotaling]

Do you know if percarbonate is porcelain safe? I'm wondering if it might have a corrosive affect on the glaze. I have some glazed wares that could use an effortless cleaning solution.

For porcelain I recommend baking soda and vinegar mix, let it sit a while, very lightly rub, wash with water, followed by a white vinegar wash to balance Ph. A 50/50 mixture of bleach can be used also, letting it sit a while. Percarbonate is safe for porcelain, glass, clay, fabric, rugs… but a step up in terms of chemical reactivity. Sometimes the quickest solution is not the most prudent, if repeat applications are a given.

@Victoria Makes perfect sense to me, thank you for the guidance.

[TeaTotaling]

That is what I tell my kids all the time, but usually the life advice that follows is not about the use of percarbonate. And falls on deaf ears.

But yeah, percarbonate works great. With clay items, but also with glass items that get stained and cloudy.

Do you know if percarbonate is porcelain safe? I'm wondering if it might have a corrosive affect on the glaze. I have some glazed wares that could use an effortless cleaning solution.

It’s absolutely porcelain safe. A soak in a little warm water with percarbonate and wipe with a Magic Eraser and you’re good.

Spoken like a percarbonate pro! Thank you @Baisao.

[LeoFox]

An old yixing hohin (possibly ROC according to experts)

Dirty!!! Amazing how some people are willing to drink from unwashed old pots like this!

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After a few hours of percarbonate revealed stubborn tarry residue!

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Proceeded to go at the Tar with abrasives (walnut powder), toothpick and brushes, followed by another percarbonate bath for 8 hours

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Had to repeat because tar is still u
Hiding in crevices. Now doing overnight soak in percarbonate

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After overnight soak, it seemed mostly done - except for some suspicious black lines around spout holes. It wasn't clear to me they were grime or just part of the clay. So I worked at it with the needle - and it was grime since i was able to dislodge what was visible to me! Not too much but stuck hard. Decided to do another percarbonate bath after this to get what is not visible

Note to Self and readers: please try not to get pot into this state- especially around spouts with filters. Sooo annoying to clean!

After needling:

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Wake up

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Done

[debunix]

What a lot of worK! It really looks nice. Hope it makes some marvelous tea for you.

[Baisao]

@LeoFox, looks great now! How did the walnut powder work for you?

[LeoFox]

LeoFox, looks great now! How did the walnut powder work for you?

When I said abrasives up there, it was walnut powder. Worked great to get a
Lot of the sludge out. Also, after using it, the mineral deposits largely disappeared

[LeoFox]

What a lot of worK! It really looks nice. Hope it makes some marvelous tea for you.

Thanks! Will be using it soon!

Gave it a bath in gyokuro

[wave_code]

Really struggling to get rid of this build up and have no idea what it is. Two rounds of heavy overnight percarbonate soak, boiling, citric acid soak... I suspected it was some really heavy lime scaling and I'll try with more citric acid but its super stuck and persistent. I got a dental scraper tool to try using that and was able to get a good amount off but getting down in the filter holes is still really tough. It's a very hard deposit whatever it is. Anyone ever had calcium or lime that was that difficult to clean out? This aside the pot was actually really clean and looked barely used.

[pedant]

maybe it's calcium citrate. no guarantees, but try boiling in a large volume of distilled water with a bit of acid added.

in the espresso machine world, there are anecdotes of formation of insoluble scales when descaling with citric acid. people say it's more prone to happening at high temperatures and concentrations, but idk if that makes sense to me.

calcium citrate (citric acid product) is only sparingly soluble... ~0.9g/L @ 20°C.
compare to ~350g/L for calcium acetate (vinegar product) at that temperature!
(limescale aka calcium carbonate is like 0.01g/L)

a personal anecdote... i just descaled my stainless electric kettle today because i was bored. i already regret doing it because the tea it makes tastes way muted now, but i digress.

most of the scale dissolved, but there are a few patches of scale on there that didn't. i actually forgot all about it until i saw it, but i think those same patches were there last time i descaled. last time, i had used citric acid for the first time in this particular kettle. i had descaled it several times in the past with vinegar. vinegar left it completely descaled. however, when i used citric acid, it looked the same as it does now... mostly bare and gleaming, but there are some stubborn, insoluble patches of scale. it looks just like normal scale except it doesn't dissolve. CO₂ bubbles (from carbonate) also don't evolve from it in acid. i think these patches of scale are the same ones left over from last time and were buried under newly formed limescale.

[botlofchaz]

maybe it's calcium citrate. no guarantees, but try boiling in a large volume of distilled water with a bit of acid added.

in the espresso machine world, there are anecdotes of formation of insoluble scales when descaling with citric acid. people say it's more prone to happening at high temperatures and concentrations, but idk if that makes sense to me.

calcium citrate (citric acid product) is only sparingly soluble... ~0.9g/L @ 20°C.
compare to ~350g/L for calcium acetate (vinegar product) at that temperature!
(limescale aka calcium carbonate is like 0.01g/L)

a personal anecdote... i just descaled my stainless electric kettle today because i was bored. i already regret doing it because the tea it makes tastes way muted now, but i digress.

most of the scale dissolved, but there are a few patches of scale on there that didn't. i actually forgot all about it until i saw it, but i think those same patches were there last time i descaled. last time, i had used citric acid for the first time in this particular kettle. i had descaled it several times in the past with vinegar. vinegar left it completely descaled. however, when i used citric acid, it looked the same as it does now... mostly bare and gleaming, but there are some stubborn, insoluble patches of scale. it looks just like normal scale except it doesn't dissolve. CO₂ bubbles (from carbonate) also don't evolve from it in acid. i think these patches of scale are the same ones left over from last time and were buried under newly formed limescale.

Did you descale your kettle because it wasnt functioning properly? I've read in a couple of places now that descaling can affect the characteristics of tea and therefore should not be done. The last place I read that was on Hojo's website... whether there is any validity to it, I'm not sure. But curious to hear if there are pros/cons to descaling.