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SmallSmallTea wrote: ↑

Fri Jan 29, 2021 7:18 pm

Hello to all connoisseurs.

I inherited few Yixing teapots (fortunately) which is very mouldy and has ugly stains all over it (unfortunately).

Read a few threads which recommend Sodium Percarbonate as cleaning agent and tried Googling it up too.

Could not find any food grade ones (or are there any actually?), are industrial grade ones safe? Are there any trusted supplier or brand?

Thanks, hope I will be able to revive my “new” teapots and get them safe for brewing once more, making cups of good tea.

Cheers!

Welcome to TeaForum @SmallSmallTea. I recommend you proceed with instructions at beginning of this topic to remove mold and stains. “Sodium percarbonate is an eco-friendly chemical which decomposes into oxygen, water and natural soda ash when it contacts with water making it biodegradable and septic safe (though it is not grey water safe due to the high salt content).” https://www.biome.com.au/blog/oxygen-bleach-cleaning/

One thing I have wondered... Is there any reasonwhy lye is not commonly a part of the discussion when it comes to resetting teapots? I recently treated a vintage cast iron pan to a lye bath and was mindblown when I saw how effective it was in removing almost a century's worth of gunk and grease. While it must always be handled with care (skin/eye exposure would be ... not good), it's food grade available and not really any reason for concern of residues after cleaning (as opposed to bleach).

But there must be a reason. Maybe clay reacts badly to it?

Balthazar wrote: ↑

Sat Jan 30, 2021 4:11 pm

One thing I have wondered... Is there any reasonwhy lye is not commonly a part of the discussion when it comes to resetting teapots? I recently treated a vintage cast iron pan to a lye bath and was mindblown when I saw how effective it was in removing almost a century's worth of gunk and grease. While it must always be handled with care (skin/eye exposure would be ... not good), it's food grade available and not really any reason for concern of residues after cleaning (as opposed to bleach).

But there must be a reason. Maybe clay reacts badly to it?

i've never used it. but in theory, using NaOH might be ok, but it depends on the concentration (pH).

what would you try to accomplish? removal of patina via saponification (basically de-greasing the pot)?

concentrated NaOH solution can etch glass, so that's why it's always stored in plastic containers. it can also etch ceramics.

since NaHCO₃ (baking soda) will also remove patina, i'd rather use that.

pedant wrote: ↑

Sat Feb 20, 2021 11:39 am

what would you try to accomplish? removal of patina via saponification (basically de-greasing the pot)?

Yes, basically to deal with something like this.

But I was mostly wondering why it is never a part of the discussion, since it's food grade, so readily available and used for many other cleaning purposes. If it can etch ceramics, then that's certainly a good enough reason to not take any chances with it!

Edit: For those interested, here's the before (first three) / after (last two) images of the vintage CI pot I cleaned up with a lye bath, a bit of elbow grease and some vinegar (at the end, for rust removal)

Decided to clean my modern ruyi pot:
After 2x 6 hour soaks with percarbonate and 1x soak with citric acid. Note the interior shot is at same orientation as the shot above. Before, it looked like modern hong ni. Now it looks like some zini blend like jiang po ni?

Brewed up a sou with this pot. Not too different after the cleaning. The pot was not very muting before. After the cleaning, still not muting. Flavors seem a bit more focused - possibly because I got rid of all the old tea residue

How would you try to clean this? With white wine vinegar and hot water? Sodium percarbonate is not an option this time (and I don't think that this would work).

It's a tea tray with a drain function and the hole(s) for the water to drain seem(s) to be clogged.

Mark-S wrote: ↑

Fri Apr 30, 2021 11:06 am

How would you try to clean this? With white wine vinegar and hot water? Sodium percarbonate is not an option this time (and I don't think that this would work).

It's a tea tray with a drain function and the hole(s) for the water to drain seem(s) to be clogged.

What is the material on-top that is lighter colored? A glaze? You could just use a paste of baking soda and lightly scrub with a soft cloth, followed by hot water wash, and then a white vinegar wash. If the drain holes aren’t too long try using a nylon cord or those nylon gum cleaners with vinegar. Otherwise they make very fine bottle cleaner brushes that might work with vinegar. If the holes don’t unclog after that, and depending on lighter material on-top, you may need to soak for a few hours in either sodium percarbonate, or solution of baking soda and white vinegar, both using very hot water bath.

@Victoria Gum cleaners are a great idea! Thank you The material on the top is also clay but the tray has rubber feet.

Mark-S wrote: ↑

Fri Apr 30, 2021 12:03 pm

Victoria Gum cleaners are a great idea! Thank you The material on the top is also clay but the tray has rubber feet.

Try a soft brush with baking soda for the clay. I’ve also cleaned drains putting a bunch of baking soda into the drain and then topping off with white vinegar and letting it do it’s thing for a while. The bubbling action helps to loosen impacted material.

Victoria wrote: ↑

Fri Apr 30, 2021 12:13 pm

Try a soft brush with baking soda for the clay. I’ve also cleaned drains putting a bunch of baking soda into the drain and then topping off with white vinegar and letting it do it’s thing for a while. The bubbling action helps to loosen impacted material.

I'll try this. Seems to be a nice tray... modern but still... Hopefully, this drain function will work after the cleaning.

Mark-S wrote: ↑

Fri Apr 30, 2021 11:06 am

How would you try to clean this? With white wine vinegar and hot water? Sodium percarbonate is not an option this time (and I don't think that this would work).

It's a tea tray with a drain function and the hole(s) for the water to drain seem(s) to be clogged.

It looks like the top doesn’t come off, and it’s unglazed clay. I wouldn’t spend too much time on cleaning, maybe a good wash on the outside. If the top doesn’t come off, the inside of this tray will eventually develop mold from tea over time.

@DailyTX That's a good point. I'll keep this in mind, thanks.

Sometimes, I tilt my pot too quickly and create a mess on the table. This is when a tray comes in handy. I think if I clean it regularly it should not be a problem. I don't plan to dispose the first infusion this way or shower my pots with it.

Mark-S wrote: ↑

Fri Apr 30, 2021 11:06 am

How would you try to clean this? With white wine vinegar and hot water?...

i agree with @Victoria. i think you'll need to use a bottle brush or pipe cleaner to manually unclog it. you probably have leaf bits or other debris gumming it up.

also, i would not use wine vinegar (white or otherwise) for cleaning because it contains unnecessary compounds that could risk contaminating your teaware. if you want to use vinegar, just use distilled vinegar aka white vinegar. the only ingredients are water and acetic acid (usually 5% solution). it's also cheaper.

similarly, i would never use lemon juice for cleaning. i would use a solution of citric acid.

@pedant

Unfortunately, there is no white/distilled vinegar in the supermarkets where I live.

My vinegar contains the following ingredients:

75% distilled vinegar
25% wine vinegar
Potassium metabisulfite

It's very cheap. About $1 for 1 liter.

Mark-S wrote: ↑

Sat May 01, 2021 4:23 am

Unfortunately, there is no white/distilled vinegar in the supermarkets where I live.

bummer. i use plain white vinegar frequently in cleaning and cooking when i want a neutral acetic flavor.. usually in saucemaking or pickling.

i know this exists in germany, but idk about where you live specifically:
essig essenz:



this is the hardcore one at 25% concentration. i wish this were readily available in US stores.

also i have heard Tafelessig is 5% acetic acid, but idk for sure.