Mold on Ivory?

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    • #132899

      Hi all,

      While working on an inventory of some objects in our collection yesterday I
      found what I’m pretty sure is live mold on an elephant figurine. The figure
      is wood but the tusks and eyes are ivory, and except for a few spots over
      the body, most of the mold was growing on the ivory tusks. I’ve isolated
      the object, but we are at a loss about how to attempt to kill the mold
      without damaging the object. We have a small freezer that we’ve used to
      treat works on paper and textiles in the past, but are worried about what
      freezing something made of these materials could do. Has anyone had to deal
      with this problem before and has some suggestions?

      Thanks so much,


    • #132910

      Hello Michele,

      I had worked with ivory in the past and do not think that freezing is a good option. If I were you I will inquire further with colleagues that are experts in this material. For example, make an initial search in find a conservator at AIC? and contact them to make further inquires. Are you sure that is ivory? What are the main characteristics of this material? a cross hatching (roughly diamond shaped cross hatching) is a good indication that the material is ivory, as are translucent wavy lines. You can write to me at and I will be happy to provide you names of colleagues that are very knoledgeable about this specific material. Hope this info will help you with your decision-making process of freezing and/or not freezing the piece. Remember that ‘condensation’ can be a very difficult thing to avoid when you get the object out of the refrigeration at low temperatures.

    • #132909

      The classic treatment for mold is to brush on or spray on a mixture of 70% ethanol in water. Just in the off-chance that there is some coating on the piece that might react, dab some of the mixture using a small brush or a swabon a spot and let it dry. The ethanol/water mixture is the active ingredient in Purell, and is the remedy recommended for artists whose works got moldy after hurricane Sandy. As a conservator who has treated a lot of moldy objects, I have not ever seen damage from this treatment – and it works!

    • #132908
      Richard Kerschner

      Now that you know that this artifact is prone to mold, try to store it in a location where the relative humidity does not go above 65% for an extended period of time or at least use a fan to move the air around the artifact when RH is high in the storage area.Here is the link for treating paintings that have grown mold after hurricane Sandy.

    • #132907

      Ethanol and/or isopropanol does not kill the mold spores in an object. Therefore mixtures of water and ethanol I do not think that are helpful.

    • #132906
      Brandy T.

      I don’t know what you should do, Michele, but it’s recommended that you DO NOT use alcohol on bone or ivory artifacts because it could lead to “excessive drying or cracking.” Refer to p. 264 of MRM5, if you have a copy.

    • #132905
      Brandy T.

      Have you looked at the “Mold” section yet on the C2C homepage? Looks like there may be some helpful resources there. Cheers!

    • #132904

      One application of alcohol and water will not dry out ivory. In fact, an alcohol/water mixture is often used for cleaning by conservators.

      The reason that a water-alcohol mixture works is that the spores, which are protected from most kill methods when they are dormant, become susceptible when they get wet. If you want to know more about mold in museums, Mary-lou Florian has done extensive research on mold and written several books on the topic.

      I am on the committee that is responsible for the web site. So far, however, we have been concentrating on insects and vertebrate pests. We are currently working on a mold section. Stay tuned.

    • #132903
      Miriam Kahn

      The Canadian Conservation Institute has technical leaflets for dealing with ivory. Contact them. Do not freeze.

    • #132902
      Rachael Arenstein

      It is confusing when someone says freeze or clean with ethanol and other colleagues and/or references say don’t. Ivory can be tricky and so there are often caveats given.

      There has been long-standing concern over freezing items with ivory/horn/bone/teeth but more and more institutions are doing this safely, regularly and propylactically. While conservative-minded conservators still are wary of this, it can be done safely and condensation can be easily avoided. The freezing procedures on the solutions page of the website give mnore information. For more on see Ellen Carrlee’s excelent JAIC article

      However, I don’t think that freezing is necessary in this case and concur with Barbara Appelbaum’s recommendation of a light swabbing with 70% ethanol. A gentle swabbing with ethanol is often a first step in cleaning ivory.

    • #132901

      Thank you so much to everyone for the comments and suggestions. We’ll obviously have to think carefully about how to proceed.

      Valeria, I would welcome any list of colleagues whom you think it might be helpful for me to contact in this situation. My email is if you would prefer to contact me that way.

    • #132900

      Michele, will reply and provide you these contacts info via email directly to you. I prefer this modus operandi so that it’s more effective. Hope these inquires to colleague will help you with the decision making process. So far, you had a lot of recommendations and options that it’s good to evaluate and then test and decide what is the best protocol for the conditions that you have in hand.

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