Caring For Go Stones (version 66)

    Keywords: Equipment

Having purchased some attractive go stones, one will want to care for them properly to maintain their aesthetic appeal. This page describes the methods of doing so.

See also Equipment Care

During my last trip to Japan, I bought a set of slate and shell go stones from a store in Sapporo. The shopkeeper gave me instructions on how to care for the stones. I'd thought I'd share them here. The cleaning method depends on the material of the stones.

When stones are purchased new, they usually have some residue on them (machine oil on black stones, wax on white stones). This is to protect the stones during transport; before actual use they should be cleaned as described below.

!!Glass (black or white stones)

  1. Warm soapy water works fine.
  2. Let them dry overnight before putting them in the bowls.

!!Slate (black stones)

  1. Warm soapy water is fine.
  2. Let the stones dry overnight.
  3. I was given a mineral oil. I was instructed to put the stones and a few drops of the oil in a plastic bag, and then to shake them around a bit. You only need a few drops! I put in too much the first time I washed them, and it made the stones an oily mess...

!!Shell (white stones)

  1. Do not use soap on shell stones! (but see Mr. Kuroki's suggestions below)
  2. Mix a fresh egg with the stones, and wash the stones in the mixture. (I was shocked at hearing this! "An egg?" I asked. "Yes," she replied. "Like from a chicken?!?" "Yes.") Has anyone else heard this?[1]
  3. Rinse the stones in water, and slosh them around for five minutes.
  4. Let them dry overnight.
  5. I was given a cloth bag and this white powder. I was instructed to put the dried stones in the bag, along with one helping of the powder, and then shake the stones in the bag. I don't know what the powder is, though.

If you have any other cleaning tips or want to expand on the above, please do so.

-- Chris Hayashida

I read this post by Roy Schmidt on I reformatted it for Sensei's Library. It's not quite as interesting as what I heard from the shopkeeper, though. :)

Roy Schmidt wrote:

Thumbing through this FAQ, I did not see anything about caring for go stones, which is a frequent question on r.g.g. Here's a translation of the pamphlet that came with my shell and slate set, titled:

!!Caring for Your Clam Shell Go Stones

First of all, each time before you play a game wash your hands. This will go a long way toward maintaining the original condition of your stones by reducing skin oil transfer during the game.

!WHITE STONES (Clam Shell)

After play, wipe the faces of each of the stones with a dry, 100% cotton cloth.

If the stones become sticky, wash them. Add a small amount of dish detergent to some tepid water and wash them by hand.

These stones are crafted from genuine clam shells. Do not place them in hot water.

!BLACK STONES (Nachi Black Stones)

Before first use, use an absorbent cotton cloth to remove the oil on the surface of the stones.

Over time, if the stones appear to be fading, add more oil. Put a small amount of machine oil (mineral type oil) on a soft cloth and rub the stones until their original lustre returns.

Fwiffo: There is a type of oil sold specifically for slate floors. I doubt it's hugely different from a light machine oil, but since it's intended for slate, it's probably perfect.


If your stones become especially sticky or difficult to clean, then seek the assistance of a specialist. You can find one by inquiring at the shop where you bought these stones.

!! Advice from Kuroki Goishi Ten

For anyone who is interested in seeing the original pamphlet on which the above translation was based, it's in photos 27-35 in the [ext] photos I took of my Go set from [ext] Kuroki Goishi Ten. It's also worth pointing out that Mr Kuroki stressed in capital letters that you MUST NOT USE OIL on the clamshell stones.

Mr Kuroki replied to my email in which I asked for more advice on caring for the black stones, whether to oil or not to oil, etc. He explained that if you use the stones often the natural oils from your skin will help to keep some oil on the black stones (and for the same reason the shell stones should be wiped clean after use).

However if you don't use the stones so much the black stones will turn a [ext] chalky or whitish colour. It's just a cosmetic thing, easy to fix. In order to prevent it you should apply oil to the black stones by putting a very small amount on a clean cotton cloth and [ext] wipe the black stones one by one. Then take another clean cotton cloth and wipe the stones again one by one. This will leave a [ext] very thin protective coating of oil on the stones.

When asking about the best oil to use Mr Kuroki originally said car oil is fine. However someone else suggested this was too thick and additive-based. When queried Mr Kuroki explained that was just a suggestion based on ease of availability. Car oil is fine but it would have to be used very sparingly. Far better is light machine oil, available from a barber's or sewing machine shop. This is very thin oil and normally used for machine blades. It should be applied in the same way as explained above. This is also Mr Kuroki's preference - a thin light oil applied sparingly by wiping onto the black stones to give a very light coating.

He also explained that as long as the board is wiped down after each use with a clean cotton cloth and the white stones are wiped clean every few games, they won't be contaminated by the oil from the black stones. Also keep the stones in their respective bowls.

Every now and again (once per year seems to be common) all the stones can be washed gently in tepid water with a small amount of light soap, rinsed clean and dried thoroughly. Then the black stones can be lightly oiled as above.

Above all don't get stressed out over the stones, just look after them and enjoy using your set as much as possible.

-- holosys


I have several sets of slate and shell stones and, not having any advice on the matter, I've washed them using cool water and dilute dishwashing detergent. I've had no problems in over 20 years. Clam shell being what it is (Calcium Carbonate?), obviously it should not be immersed in anything that would interact with it chemically.

I think the white powder Chris mentioned is wax. White stones arrive with a wax coating that gives them their shine and depth.

Actually, Bob's right, it's wax. It was confusing because the bag was labelled "ibotaro." Read one way in Japanese, "ibo-taro," means "wart boy." I thought it was a brand name. Read another way, "ibota-ro," it means something else. I think it's the name of the tree that the wax comes from.

-- Chris Hayashida

The "ro" part means wax. Chris, your new nickname is "ibo-taro"...

-- Fhayashi

What about ING stones? I'm guessing the method described above for glass stones would probably work, just curious if anyone has ever washed/cleaned a set before.

-- Jim Kiraly

eng60340 i managed to shine the black ING stones with the plastic bag and oil trick. for the white stones, i've used hot water and detergent to clean them. right now i am trying to figure out a way to add a gloss to the white stones. any experienced suggestions ?

for white stones i'd recommend an acid-free wax polish made from mineral oils- ok, i'm a conservator and usually mix my own, but the ingredients are hard to get-that stuff used for polishing cars is acid-free, mineral-oil-based and microcristalline, so it should be ok. it can be diluted in various solvents, if it should be too thick. use sparingly, of course, or the stones will get sticky. shell doesn't take acid well, so it's important to wash the stones once in a while with a mild detergent. rinse with lots of hand-warm water that's because the sweat and oils from your hands turn sour with age. also, don't use natural oils or waxes such as bee's wax- it is ok for some time, but will destroy the surfaces of shell stones after 3 or 4 decades. blade oil should be ok, too, as it is very stable and acid-free. sorry for my poor english, i hope you can understand what i'm trying to say... grimalkin

Bob McGuigan: Here's a link for a supplier of Renaissance Wax, a product often used by museaum conservators: [ext]

For Shell stones, Try to clean with milk (It can be wait in milk for better results but test it on one stone) and write the result here.mehmet

I found that car shampoo soap with wax worked well on white shell stones. Ast?

[1] Chris Hayashida: Update: Well, I finally got around to washing my Go stones. Last week at the club, I noticed they were getting quite dirty. I tried to rub off the gunk on the shell stones with a paper napkin while I was considering moves, but the gunk was sort of stuck on there.

Since I had the time this weekend, I decided to try cleaning the stones with egg. I separated two eggs and mixed the stones with the egg whites in a Tupperware container. Surprisingly, the gunk came off the stones quite easily. I didn't have to rub the individual stones. I don't know why, but it seemed to work really well. The mixture even seemed to bubble a bit, like a soap. I rinsed them off and laid them out to dry. I'll mix them in the bag with the ibotaro later. I'll report again in a few weeks to tell you if 1) the stones start smelling like rotten eggs or 2) anyone using my stones gets Salmonella poisoning. :)

Ship Passing in the Night? - Salmonella? Unlikely, but small child hazard? Maybe. Egg yolk is an ancient artist's material, grind with pigments to make paint for fresco. This line of thought suggests using mayonnaise to clean go stones... hmmm...

XCMeijin - A whole egg? Wouldn't it be a little better to only use the egg white? Or is there no difference? I could cook the yolk later and eat it in preparation for a big match, i guess :P

CharlesSutton The [ext] advice at Yellow Mountain Imports mentions the egg trick, too.

koreangrl8? you guys for got jade? stones .. same way

  hot water and soap just let it soak. I have black
  and white jade? stones they make pretty sounds
   on the go board.

[] Care of Shell Go Stones: Molar solubilities of CaCO3 (main component of sea shells) at various pH's are given in the Table below. Notice that CaCO3 is relatively soluble in an Acid solution, and is relatively insoluble in a Base solution. This feature is used by Geologists to test for carbonate rock (calcite). Calcite `fizzes' when HCl (an Acid) is dropped on it but has no reaction with NaOH (Base). Why does it `fizz' with HCl? As CaCO3 is broken down with HCl, CO2 is produced along with CaCl? and H2O. Note that Water is neutral at pH of 7.0, HCl is an acid (pH < 7.0) and NaOH is a base (pH > 7.0). Almost all soaps are alkaline (base) (see wiki: soap) and mild solutions of alkaline soap will be safe for shell stones.

Solubility of CaCO3 as a function of pH

pH molar solubility

2 170

4 1.70

6 0.020

8 0.0011

10 1.4x10-4

12 0.0092 7.8x10-5

Carnauba Wax, is one of the hardest most water repellent waxes known (hard as cement in natural form). This wax is good for shell stones after cleaning. Make sure that you use a natural product or one that has a pH of 7.0 or higher (alkaline), as some wax solutions may have the pH manipulated to an acid (pH < 7.0) for specific purposes not compatible with shell stones.

Natural Carnauba wax:

Melting point 78C to 85C (depending on type of Carnauba)

Flash Point 300C

Acid Number 7.0 (mg KOH required to neutralize 1000 mg of wax, this is not a pH number)

                  (SLIGHTLY acidic, but very little wax is used, and it is relatively unavailable to the shell i.e. bound in the wax)

Saponification Number 85 (mg KOH required to saponify (make soap) 1000 mg of wax)

                   (larger # means more moles of wax molecules i.e. smaller molecular size)

Specific Gravity 0.97 (slightly less dense than Water (1.0))

A thin coating of a pH neutral wax is helpful because human sweat can be a bit acidic, which is bad for CaCO3 (shell stones). Depending on diet and other factors, the pH of sweat can vary greatly. A healthier diet, more vegetables and fruits, and less meat and dairy products tends toward a more alkaline human system...

Sinprejic: Interesting discussion, one thought I had was it might be good to PH test your tap water or any other water you are using to wash clamshell. Tap water PH can vary between 6.5 and 8.5[2] which doesn't sound like a lot, but pH is a logarithmic scale, so pH of 6.5 is 100 times as acidic as 8.5. Any pet store or place that sells fish should have pH test kits for 5-10 dollars (US). One of the first steps in setting up an aquarium is to check and balance the pH into the range your fish like. However once you've measured it the pH out of your tap is unlikely to change unless your town changes it's water supply. There are chemicals for balancing pH in aquariums but I don't remember what they are, let alone how they'd interact with Calcium Carbonate. Another thing I'd like to know is how the above molar solubility rates translate into rates of corrosion, and at what point is it significant enough to worry about.

Another thought: while soaps may be safe from an acidity standpoint, soaps often contain perfumes, or dyes that could potentially adhere to the shell... your stones might end up smelling like lilac if you use something that has a lilac scent. Maybe that's good maybe that's bad :)

[2] [ext] (I looked for a non-commercial link to pH drinking water standards for about 45 min if someone can find one that would be preferable)

[] Sinprejic brings up very good points, and the link is also very useful. While most soaps can neutralize even the most acid tap or well water it will not get rid of minerals and other organic compounds, and you still have to rinse well. If your water is questionable, and now sinprejic has me thinking, just use distilled water, especially for a good final rinse. Its pretty available these days.

Also perfumes and dyes are probably not good under any circumstances. Perfumes are typically complex molecules. Who knows what they will break down into. Dyes can also break down and change color... Both could eventually stain the stones or react with the CaCO3 in some way other than simple acid reaction. I'm no expert but I have tried many soaps over the years even things such as natural oil based soaps i.e Castile, etc. Some have been nice others even though expensive and highly natural did not rinse well at all and left a noticeably sticky film. A plain dish soap used in mild solution is probably best. It is made to rinse well (for no spots or film on the dishes). The cheapest ones are likely to have the least perfume or color. If you can find it buy clear dish soap. Then rinse very well with distilled water.

  • avoid temperature jumps when washing stones (may split)

Indeed ToBeMasterEdited...

Caring For Go Stones (version 66) last edited by axd on February 11, 2008 - 23:39
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