Preferred methods for cleaning porcelain

[grwcm]

Hi, folks. I usually use Cafiza, a product made by Urnex, for cleaning my porcelain teapot and mugs. With a half teaspoon and boiling water, the tea stains disappear in short order. Cafiza basically releases hydrogen peroxide when mixed with water. After a couple of hours soaking I rinse thoroughly and tea stains are gone. It's not cheap, but a container lasts an awfully long time and does the job.

[betta]

Cafiza basically releases hydrogen peroxide when mixed with water.

Hydrogen peroxide is one of active components in bleaching agent.

[bagua7]

Baking soda and acid are abrasive chemicals, will be useful for inorganic stain, such as calc, etc. Since they're abrasive, you should try to avoid using it as best as you can.

I would like to clarify that statement:

Bleach is an acid (yang) (Cl2(aq) + H2O(l) ---> 2H+(aq) + Cl-(aq) + ClO-(aq)) and will slowly "decay" the glaze of the porcelain.

Baking soda (Na2CO3 + CO2 + H2O ---> 2NaHCO3 ) is slightly basic (yin) (the bicarbonate disociates into HCO3 ---> CO2 + OH- ) and will not damage the glaze of the ceramic.

[betta]

Baking soda and acid are abrasive chemicals, will be useful for inorganic stain, such as calc, etc. Since they're abrasive, you should try to avoid using it as best as you can.

I would like to clarify that statement:

Bleach is an acid (yang) (Cl2(aq) + H2O(l) ---> 2H+(aq) + Cl-(aq) + ClO-(aq)) and will slowly "decay" the glaze of the porcelain.

Baking soda (Na2CO3 + CO2 + H2O ---> 2NaHCO3 ) is slightly basic (yin) (the bicarbonate disociates into HCO3 ---> CO2 + OH- ) and will not damage the glaze of the ceramic.

Bleach is oxidating agent, does not limited only to Chlor. Chloride is only one of the most widely used bleaching agent in textile industry. For food industry, peroxides are widely used. One of them is hydrogen peroxide. Why? because it basically reacts to form water.

This bleach will attack organics as well as unprotected metallic surface, such as wrought iron.
The basic material of the porcelain is silica and the metallic glaze has been fired at a very high temperature and therefore stable. Glaze serves its function to protect the surface beneath it.
At low concentration of bleach, you can remove the organics far more effectively instead of using high concentration acid/base.

The fact that acid is corrosive/abrasive is self explanatory. However many don't know that base is also corrosive. Detergent and soap is one of example of the so called weak base. We know from daily phenomena that high concentration detergent does not necessarily be effective to remove organic stain on clothes. Otherwise people don't need to invent bleach.
You can compare how much more baking soda is required to remove tea stain from antique yixingpot rather than small amount of bleach.
People usually use baking soda paste in combination with rubbing motion. This adds additional mechanical abrasion.

Hope it clarifies that statement.

[David R.]

Bought myself a little porcelain pot (a set actually) on eBay for gyokuro. Here's the result of my cleaning using dental tablets.

BEFORE :

[David R.]

AFTER :

[Chip]

Wow, that is pretty amazing!

Exactly what tablets did you use? I have a Hagi that I am considering "starting over" so to speak. I think Buzz mentioned he used tabs for a Hagi piece with outstanding results.

Oh, and very nice Kyusu! I like the landscape motif of this one.

[David R.]

I honestly took the cheapest model at my local drugstore. I doubt you'll find the same one outside of France. But before, I used Stéradent with the same result. It only leaves a slight minty odor that disappears after a night immersed in water.

I know people who use such tablets to reset yixing too. No residual flavors at all. I've tried it myself.

I guess dental tablets have the same molecules than baking soda. I'll have to check later.

Here's the link to the porcelain set I bought if you're interested.

At last a pic of the "making of"

[wyardley]

I honestly took the cheapest model at my local drugstore. I doubt you'll find the same one outside of France. But before, I used Stéradent with the same result. It only leaves a slight minty odor that disappears after a night immersed in water.

I've used Sparkle-Dent before. It's not flavored / scented, which is not a big deal for porcelain, but worries me a bit more with Yixing pots.

http://www.usdentalcorp.com/product_inf ... 29f401a293

If I understand correctly, denture cleaner is essentially an oxygen bleach, so I think you could get the same effect by using a diluted hydrogen-peroxide solution or some other kind of oxygen bleach.

[David R.]

I didn't know that it existed without "aroma." Good to know, thanks.

Honestly, after a day soaking the yixing into water and a raising session, it is hard to distinguish any residue of flavors. I know some pretty serious drinkers who did it with old yixing pots and didn't feel a thing. It sounds scary but it is ok.

But of course a flavorless tablet is better.

[entropyembrace]

Baking soda and acid are abrasive chemicals, will be useful for inorganic stain, such as calc, etc. Since they're abrasive, you should try to avoid using it as best as you can.

I would like to clarify that statement:

Bleach is an acid (yang) (Cl2(aq) + H2O(l) ---> 2H+(aq) + Cl-(aq) + ClO-(aq)) and will slowly "decay" the glaze of the porcelain.

Baking soda (Na2CO3 + CO2 + H2O ---> 2NaHCO3 ) is slightly basic (yin) (the bicarbonate disociates into HCO3 ---> CO2 + OH- ) and will not damage the glaze of the ceramic.

uhm...except chlorine bleach is NaClO which dissasociates into Na+ and ClO- in aqueous solution and it´s pH is approximately 11...it´s very strongly alkaline(basic) not acidic.

also most glazes are glassy and are highly resistant to corrosive attack by acids.