Hi all!

After years of playing Go off and on, I have decided to commit to playing regularly because I really do love the game. I have been lucky enough to find some local players who are a good match to play with, and one of my friends convinced me to buy a nice set of stones.

I found some used size 34 slate and shell stones from Japan on eBay; honestly it was a pretty good deal. I fully expected some yellowing to be present which was the case, but what I was not expecting was for one of the 180 to be plastic and smaller than the rest (oh well, it's only one, and I'm starting a dialogue with the seller about that, assuming it was an oversight given they were used).

That being said, I have attached a couple of photos of the most worn shell stones so if there is any damage not characteristic of regular use, maybe that can be identified (the seller has not responded to my questions about them in around a couple weeks).

My main questions: I have heard that sometimes resin from bowls can get on stones, discoloring them more or less permanently. In this case as I understand it, the hydrogen peroxide approach does not remove this. That being said, I hear that a botched hydrogen peroxide cleaning can lead to permanent damage on shell stones as well. I am wondering if the wear on the pictured stones looks consistent with either resin or hydrogen peroxide damage. My guess is that they're yellowed from years of regular use. Either way really I'll likely do the hydrogen peroxide job on them as detailed in this link:

https://erythen.wordpress.com/2015/09/2 ... go-stones/

Thanks in advance for any help! Happy Going!

EDIT: shrunk the images for ease of viewing.

I have seen a lot of stones look like that in Japan because of the intense smoking in go parlors. I don't know if this is caused by smoke, but it could be. I think yellowing is common from overuse and lack of care. If you haven't already, you should try to just clean them with a mild soap and water and see how they look. I have never done the peroxide thing before, so I cannot comment on that.

It's not uncommon to find a few plastic or glass stones in an old used set...often used as replacements for lost or broken stones. Back when I was selling, I'd try to remove these when I came across them, and I actually ended up with little over a full set (albeit mismatched).

Some of the stones look like they might have gunk on the surface. If so, a soak and some light scrubbing with a cloth will take that off.

The discoloration looks like normal wear, most of what I can see will disappear with hydrogen peroxide; though some of the deeper discoloration (like in the bottom right stone in the first image) may remain. Just make sure to rinse the stones well before setting them out to dry. For a good comparison (if you're not in a hurry) clean a few stones and place them next to the others.

When you're finished cleaning, post a few pictures

Thanks guys!

Cool to hear from you Erythen, the person behind the tutorial I've been referring to! Now that I've heard your recommendation I feel more confident about doing the hydrogen peroxide clean and I will gladly post pictures, I'll even do a comparison one with just a few stones.

That being said, I don't know how much wax may or may not be left on these. If there isn't much wax left on the stone can hydrogen peroxide hurt it? How quickly do I have to get the hydrogen peroxide rinsed off of a stone once it leaves the liquid? Admittedly I am a bit paranoid about permanently damaging my investment.

I've only seen damage from hydrogen peroxide once and that was when I was in a hurry and neglected to rinse the stones, leaving them out to dry all night. It was with one of the earlier sets I cleaned and I was using 35% H2O2 (not the normal 3% you find in stores). It was a size 25 standard grade set so not too traumatic, but it was a lesson harshly learned.

The damage to the stones was...interesting. There were spots that appeared rough and bright white, and patches of the wax polish looked as though something had eaten through it. This was even more clear when I held a light behind the stones. The shape didn't change and they were still playable, so I sold them at a massive discount. I wish I understood the chemistry behind it. I might still have pictures of the damage somewhere...if I happen upon the photos I'll post them.

You won't need to worry about rushing to rinse the stones. You could easily remove the whole set and then rinse them under the sink or shower without any problems.

If the wax polish has worn off then the surface of the stones will be a bit rough. I've only seen a few used sets like this, and they were in abysmal condition.

I hope this helps .

Here they are after their soap soak. I found a "no dyes or strong perfumes" dawn soap that seemed good for this. Honestly, they all look so white now compared to before that I wonder if the hydrogen peroxide soak is even necessary.

Nonetheless, I figure it won't hurt, and those I had pictured previously do still have noticeable browning on them, so I might as well do the hydrogen peroxide step for all of them. Also attached are two of the most noticeably browned stones. I'm looking forward to see how this goes.

The H2O2 soak begins! I took one more before picture of the most browned stones to put alongside an after picture once the soak is up.

I notice there are some air bubbles on some of the stones. Mostly I've kind of shifted the stones by squeezing the container around them to get them out. I know it sounds silly, but if there are air bubbles on the stones could those be spots where the hydrogen peroxide could cause damage? I imagine this isn't much of an issue.

Not sure how much Catalase may be in the wax coating and the shell material, but see here: https://en.wikipedia.org/wiki/Catalase. IF this is the reason, then the bubbles would be oxygen.

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The air bubbles are normal, and there are generally quite a few when I use 35%.

Small update:

WOW! They've been soaking in peroxide for around 20ish hours and just looking at them in it I cannot see any of the brown on any of them. I didn't expect it to be completely removed, but it looks like it may very well be, unless all the brown spots somehow shifted out of view. They're looking very bright and nice.

I'm pleasantly surprised and very pleased. Because these snow grade shells were used I got them for a very low price compared to when they're new, and they're going to just about look like new by the time this process is done. From the looks of it, the after pics will be more drastic than I expected.

In short, I can vouch for this process, it works wonders on shell go stones.

H₂O₂ !

Back with pictures. I have rinsed off the H2O2 and they are laying out to dry for the night. Waxing comes next, possibly tomorrow, possibly later this week. Depends on when I get time.

Hi B,

Which type of wax are you planning to use ?
And have you had any experience with waxing shell stones before ?
You may want to just use your freshly H₂O₂ cleansed shell stones as-is, and see if you like the feeling.
Then you can still decide if wax is necessary. Just an idea.

I bought the carnauba wax Erythen recommends. Because I already spent the money, I don't really want it to go to waste (although I do have the receipt and could return it).

I just assumed it was a necessary step after soaking in H2O2. If it's optional then I may consider returning the wax.