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Ivory Restoration


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I received this inquiry today and hope that there will be some help for this project. I did send this inquiry message to several artists who might know some answers, but I hope that some of the knowledge will also be shared here. I added my response below, but I have no experience with ivory restoration, so my thoughts are only that, not experienced advice.


The inquiry:


Dear Janel,


I hope this email makes it way into your hands. I got your address from a

three-year-old posting on "The Carving Path" forum.


I'm a retired American woodworker/restorer living on the northeast coast of Brazil.

Restoration work does not lack here, but I was recently handed a real challenge:

restore a small picture frame, approximately 9" x 9", inlaid with ivory. I suspect

the ivory was cut from piano keys. Let me put the matter frankly before you: it's

driving me nuts! I can't get it clean.


The ivory has numerous amber-colored stains and spots of grayish mold as you can see

in the HUGE file photo I sent you. The amber stain, I'm certain, came from the

underlying wood frame, which got wet and leeched "something" into the ivory (tannic

acid?). The gray mold staining, of course, needs no explaining.


There apparently was no effort made to seal the wood prior to gluing the ivory onto

it. The artist just plopped the inlay right onto the wood and held it in place with

what appears to be some kind of crummy horse glue. When lightly moistened, the

individual ivory pieces are easily lifted from the wood base.


At this point I've tried about everything: milk, lemon juice, salt, sanding,

exposure to sun, ethyl alcohol, immersion in turpentine, harsh language and etc.,

etc., etc.. Nothing is working very well.


All of this to say that I think it might be time to drag out the big gun: boiling

the ivory. And this is really why I'm writing you. I took a small piece of the

stained ivory and boiled it for about fifteen seconds in Chlorox. It definitely

whitened the ivory, and, of course, gave it a rather chalky appearance.


We all know and love that famous creamy patina that good ivory acquires with time.

Yes, it's a shame to lose this, but, dammit, this is war! So I have three questions

for you:


1. Can you think of any other method that I might want to try to clean up this

ivory before I cast it into a boiling pot of Chlorox?


2. Through your years of trial and error, do you have any refinements to the

boiling process that you might care to pass on to me? Or is it really that simple:

place ivory in boiling Chlorox, for X amount of time, then immerse in vinagar bath

to stop process?


3. If I do make the (literal and figurative) plunge and boil the stained ivory,

what can be done "post-boil" to restore at least some of the natural beauty and

sheen of the ivory?


I, of course, plan to discuss all this with the customer before making any radical

moves. And I promise not to hold you responsible if the results aren't so good.

The way I see it, there's not much to lose. The present condition of the ivory

renders it too ugly to be seen in public. At least with a boiled and whitened ivory

there is a chance to make it presentable.


Janel, I wish you all the best, and thanks for taking the time to read all this.

I'm sure you sense my desperation.


I await your response.






--= --= --= --= --=


My response:


Hi Steve,


It is good to meet you. Thank you for writing with your questions. I hope that some help will be found to improve your odds with the restoration of the picture frame ivory.


I would like to send your message to some individuals who might have better knowledge of how to achieve your goal of removing the stain from the ivory. I would like to post this also on The Carving Path forum, though the summer seems to have distracted many of the members from logging in. The results there may be longer in being posted there.


Questions for you Steve:

1- Do you know that this is elephant ivory or mammoth tusk ivory


2- Are you positive that the ivory was not already stained at the time the frame was made? In my experience with mammoth tusk ivory, some of it is stained from having lain in the earth for many thousands of years. (I do see evidence of uniform staining around the opening of the frame that could be evidence of staining after the frame was made, but could have come from decades of cleaning the glass from the front side using colored glass cleaner, or who knows what. You are able to see the other sides and have a better idea of that area.)


My first response to boiling in bleach is one of urging caution and waiting for other options to be tested. I hope that there is a best way, one that will not damage the ivory significantly. The following are just rambling suggestions, not from my experience with whitening ivory:


- Have you tried hydrogen peroxide? That may be gentler than bleach. It whitens teeth and has been added to many tooth care products these past years. There may be a resource for a stronger percentage than the over the counter (3%)


- I believe that wood bleaching kits have one part that is peroxide, but that is just a vague memory. We discussed bleaching wood on The Carving Path at some point in time. Use the SEARCH function to find the archived information about that topic.


- I have not tried this on ivory, or in my case mammoth tusk because that is what I carve:

At home, with stubborn stains on white clothing that will not respond to the average spray treatments, peroxide or bleach, sometimes a product with Oxalic Acid (brand name: Bar Keepers Friend, a cleanser and polish). It comes in both liquid and powder. The scrubbing agent or the powdered ingredient in both is sometimes a nuisance with clothing, but usually I moisten the fabric stain area and put the product on. It is the acid that removes the stain. I have very hard water here with iron content, and this is the trick I use to remove stains under the arm or from milk on clothing which attracts the iron from the water for some reason.


I do hope that a gentler solution will be discovered. I also wonder if there may be guitar builders who use or used ivory on their instruments who may have experience with whitening the ivory inlay.


Now to send your message and mine to others who may be able to add helpful information to your knowledge base.


My apologies for sending a greatly reduced file size image. My home internet connection is extremely slow today, and I have to keep downsizing the image until I can get one to upload to my email server. I have cropped, resized and adjusted for White Balance the image that you see attached to this message. The original file was 3.5 MB



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Guest Clive

In my experience there really isn't a good way to remove all stains from ivory. I'd strongly recommend that any bleaching technique be used with utmost caution... if at all. As a last resort in very limited circumstances I've lightened ivory with various bleaches in the past but found that the process breaks down the structural integrity of the ivory which limits the restoration of a polished surface.. it becomes rather chalky, soft and and grimy.


Saying all that... I have found that Vulpex liquid soap can be very effective and would certainly recommend it as a first step.



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Hi Steve,


- Have you tried hydrogen peroxide? That may be gentler than bleach. It whitens teeth and has been added to many tooth care products these past years. There may be a resource for a stronger percentage than the over the counter (3%)




Beauty supply stores have stronger peroxide available. Be careful using these because your body has a natural enzyme in it that make the peroxide work. When the stronger peroxide reacts it can give offf enough heat to boil water and cook flesh! Some health food stores and trendy grocery stores have peroxide based "bleaches".


Oxygen releasing powder cleaners might work.


And you can try over the counter teeth whitening strips/cleaners. They're mild enough for the mouth so they shouldn't do any damage.


I haven't tried any of these methods so proceed slowly.


For mechanical cleaning of delicate picture frames antique dealers sometimes clean pictures with a slice of bread.


Good luck



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:blush: I've been wondering if I should post this or not, but here goes...

As a practicing paper conservator, I see this sort of approach to treating objects often in my profession, and have to come out and clearly say it is wrong. In this day and age, if a 'restorer' doesn't know enough to know the difference between one bleaching agent and another, who sees stain elimination as a battle to be won and retouching as a normal follow-up to over-cleaning, perhaps they shouldn't have taken on the job.

Please realize where the limits of your knowledge are, and resist the urge to compete against the ivory frame. Take Clive's advice and use a mild surfactant- Vulpex or Orvus- and let things be. You'll have enough of a problem on your hands reattaching the ivory to the wood after you've applied the soap and rinse it with water.

There are poultice and cleaning gel applications that can be used to lighten the staining further, but they're really up to someone who has more experience.


and then we get advice from people who then confess that they really haven't tried any of the methods they're recommending...? natural enzymes in our bodies that make H2O2 work?


Finally, from the photos, the frame appears like it might be made of bone.


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and then we get advice from people who then confess that they really haven't tried any of the methods they're recommending...?



Just offerering a different suggestion rather than boiling in bleach. I will gladly retract my suggestions and leave the discussion to those more experienced than I.


"natural enzymes in our bodies that make H2O2 work?"


Actually speeds up the reaction. Catalase helps decompose the peroxide that our bodies form naturally. Yeast and liver also work as a catalysts for peroxide. Ultraviolet light also speeds up its decomposition hence the brown bottles.



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Guest Clive

IF this was a job I really needed to do.. and I don't think the piece has any historical value or is very old or has any real quality worth preserving.. and also because there is a difference between restoration and conservation... I'd simply lift off all the "ivory" sections and using them as templates recut new ones out of clean material... say a little over half a day for that and glue.. and the rest of the day to sand and polish... and as they say in Yorkshire.. Jobs a good'un.

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Hi Steve,


Although I have already replied to your message, I will post the reply to add to the discussion.


My experience with Ivory and related materials comes from formal study in the conservation of museum artifacts, and 20 years of experience in the conservation of artifacts at the Canadian Conservation institute, and the Canadian Museum of Civilization Corporation.


First off, I would say that the material is bone, and not Ivory. I deduce this from the presence of a few grainy pores that seem to be evident in the image that you sent. These are known as haversian canals, and carry nutrients through the living bone. They are not present in any type of ivory, and their presence rules out the possibility that this material would be ivory. However, the resolution on the image was not that clear, and I could be mistaken about the pores. (Although now that I see the images more clearly, I am more convinced that the material is bone, or perhaps thinly sawn antler, as indicated by the greyish patches.)


If they are present, this could explain why the stain has migrated throughout the material. Bone is similar to wood, in that the porosity tends to allow stains to leech deep into the fabric of the material, where it is virtually impossible to remove. Also, many stains in bone tend to come from fat residues that are present throughout the material, if it has not been properly de-greased. With time the fat turns dark yellow to brown. Again, something that is not found in Ivory.


If you have already tried abrading the surface, and the stain has not disappeared, then it is deeply ingrained, therefore, regardless of the material, the stain that you are facing will be virtually impossible to remove.


I would suggest that you avoid boiling it at all costs. This will cause irreversible damage to the construction, dissolve the hide glue, and likely warp all of the materials beyond any hope of saving the piece as a whole.


In a museum environment, we would not consider removing this. It is just accepted as part of the aging process, and a developing patina. The piece was probably never white to begin with, and trying to make it appear white would be an attemt to return iy to a state that never existed.


If I were faced with this piece, I would make sure that the piece was stable, in that none of the plates were loose or coming off. I would clean it first with soapy water to remove any dirt, then swab the surface with acetone to remove any further dirty oils. If it was a bit dull-looking, a light coating of paste wax, such as Renaissance Wax would improve the appearance.


While I was at the Canadian Conservation Institute in the late 80s, doing my internship, my instructor was successful in removing similar but darker stains from a large whale bone sculpture that was leeching brownish ransid whale oil. This was a very complicated proceedure that involved isolating the sculpture in a bath of 111 trichloroethane (a dry cleaning fluid) to leech the fats out, in a large fume hood. The dirty solvent was distilled to remove the fats, and the clean solution was re-circulated over the sculpture until no fat was distilled out. AS I recall, it took a couple of months. Obviously a very complicated proceedure that can not be done at home, but also to show how the stain is usually in the oils embedded in the material. I just threw this in out of curiosity.


Hope this helps,



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Thank you folks for your participation in helping Steve with this project. Here are excerpts from the message I received from him last evening:


Hi Janel,


Well, what can I say? Thanks to you, I've got a team of people stretched halfway 'round the world now working on solutions to get those ugly splotches off my picture frame.   You make a guy feel important, Janel. Thanks. 


You have perhaps by now read the exchange between Phil White and myself? Phil thinks it's bone --not ivory-- that I'm dealing with here and that changes the prognosis a bit. Phil thoughts have that unmistakable ring of authenticity. When he tells me that boiling is a poor option in any event and that the owner of the frame should simply appreciate the piece as it is, I believe him and I can make the customer believe it too.


Others --notably Natasha-- concur with Phil. Boiling is the cure that's far worse than the disease. SO...no boiling. 


As I mentioned to Phil, I keep beavering away day by day with very fine grit sandpaper, which has undeniably improved the looks of this ugly duckling. (Only after three days of this was I able to really convince myself that I was seeing improvement. Builds character, this sanding with 1200 grit.)


I'm going to take Natasha's advice and lay on some peroxide --another area where various artists and professionals seem to have agreement. Peroxide good, Chlorox bad, very bad. It can't do any harm is the message I get from most professionals.


All this to say, it's been kind of fun. My deepest thanks.


All the best from just a little south of the equator,



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