Connecting to Collections Care

 View Only
Expand all | Collapse all

Mildew on leather

  • 1.  Mildew on leather

    Posted 05-31-2019 18:29
    Hi Kathleen,

    At our museum we have saddles and an 1890's old buggy One day a visitor came in that refurbishes buggies. She was very
    excited to see the original leather on part of our buggy. She told me to use white vinegar to clean the leather.
    I tried it on a hidden area first(as per her instructions) to make sure it wasn't going to make matters worse. It
    didn't. So I cleaned the leather panel with white vinegar. I used a q-tip to spread the vinegar and let it air dry.

    For the saddles, I purchased saddle soap and cleaner from a Farm supply store. I put it on the saddles with a
    soft cloth. I followed the instructions on the cleaner.
    I also google this and received four or five solutions for removing mildew and mold off leather products.
    There are youtube videos showing exactly how to take care of leather products-baseball gloves with mildew. Check them out for instructions.
    Hope this helps.

    Julie Thompson,
    Guardians of the Eagle Point Museum


  • 2.  RE: Mildew on leather

    Posted 06-01-2019 11:47

    I would like to direct everyone's attention to a series of guides the AIC has prepared to help you.  The Caring for your Treasures handouts are available for download here

    On page two of Caring for Books, that handout mentions:

    "In the past, leather books were often oiled to improve their feel and appearance. Unfortunately this can also cause stains, make the leather sticky, and degrade paper. Recent tests have shown that dressings are only cosmetic and do nothing to prolong the life of the leather. Consult a conservator before using dressings . . . "

    I understand that remedies like vinegar or saddle soap are sought with the best intentions for preserving collections.  That being said, these products can cause additional, long-term harm and are not recommended.



    ------------------------------
    Keara Teeter
    Graduate Fellow, Class of 2019
    Winterthur/University of Delaware Program in Art Conservation
    ------------------------------



  • 3.  RE: Mildew on leather

    Posted 06-01-2019 18:31
    I am a wooden objects conservator who specializes in conservation of horse-drawn vehicles.  In addition, I was the managing conservator recently for a mold remediation project at the Mark Twain House & Museum in Hartford, CT.  We removed mold from over 5,000 objects varying from books to ceramics to metals to glass to leather to finished and unfinished wood to textiles to paintings.  Our general procedure was to examine the object for stability, and if safe, vacuum with a HEPA variable-suction vacuum (many ordinary shop vacuums can be converted to HEPA variable suction very inexpensively, often for less than $50).  For many objects, this was sufficient.  If additional removal was necessary and the object was non-absorbent, we used a soft cotton pad or cloth or swab SLIGHTLY dampened with distilled water.  Of course, we tested to make sure it was safe before moving forward.  With literally only a handful of exceptions, this is all we used for mold removal on the 5,000+ objects. 

    Vinegar contains a relatively impure acetic acid.  Acids are not healthy for leather.  Have you ever seen red "rot" in leather - it turns red and tears and powders?  It is caused by acid generally not sufficiently removed in the original processing of the leather when it was made beginning in the mid-19th century and later.  Always use distilled water first if the surface is safe for "wet" cleaning (this refers to any liquid, not just water).

    I fully concur with others that saddle soap and other commercial products should not be used on historic objects, including horse-drawn vehicles.  If you are trying to maintain your own leather object for a few years, these products may be useful.  However, over hundreds of years, the goal of preservation after all, they do not age well and can cause more damage than had they not been applied.  In general, I recommend not applying anything to leather of horse-drawn vehicles.  If the leather appears to need some treatment other than that described above, it should be referred to a conservator for advice. 

    I hate to say this for the umpteenth time, please get advice from a fully trained and qualified conservator, not some local restorer or refurbisher or u-tuber.  Conservators spend much of their treatment time trying to undo harmful processes or materials (sometimes unsuccessfully) that such individuals recommended or have done to objects  There is a reason that conservators spend 4 years getting an undergraduate degree in chemistry, art history and studio art, then 3 years in graduate conservation studies, plus in many cases, post-graduate fellowships and internships.  There is a LOT to learn!

    ------------------------------
    Marc Williams
    President
    American Conservation Consortium, Ltd.
    acc@conservator.com
    ------------------------------



  • 4.  RE: Mildew on leather

    Posted 06-03-2019 17:13
    I was wondering about the use of isopropyl alcohol applied locally with a cotton swab? I was expecting to see this as a suggestion but was surprised to see I had not. I have a similar situation with leather on the inside of book covers, which show spots of mildew. I was hoping that the alcohol and mechanical swabbing would address both the mildew and staining.

    ------------------------------
    James Davis
    Charleston Library Society
    Charleston SC
    (843) 723-9912
    ------------------------------



  • 5.  RE: Mildew on leather

    Posted 06-03-2019 21:56
    James,

    Many leathers have coatings or other treatments applied to their surfaces.  These can be soluble in alcohols.  This is especially true of leather on horse-drawn vehicles, as they were designed to be outdoors and most certainly saw rain/snow/mud in use.  In the 19th and early 20th centuries, natural resins were commonly used as coatings, and many of these are highly soluble in alcohols, particularly in ethanol.  So I would be very hesitant to use solvents to clean historic leather unless extensive testing is done.  And I certainly would not recommend doing this to a lay person who does not have any conservation training.  If wet cleaning is desirable (and tested safe), stick with distilled water unless the generic you has additional skills and experience.

    Marc

    ------------------------------
    Marc Williams
    President
    American Conservation Consortium, Ltd.
    acc@conservator.com
    ------------------------------



  • 6.  RE: Mildew on leather

    Posted 06-02-2019 15:05
    I fully concur with Marc and Keara about the leather treatments. Also, I'd like to add to avoid any of the commercial "leather dressings," as they will deteriorate leather over the long-term, even through the leather looks supple after immediate application. I hope this helps.

    ------------------------------
    Georgia Fox
    Professor of Anthropology
    California State University, Chico
    Chico CA
    (530) 898-5583
    ------------------------------



  • 7.  RE: Mildew on leather

    Posted 06-02-2019 20:54
    I have to say, Keara, Marc and Georgia, that your advice has hit it out of the park, so to speak!
    Regards,
    Meg

    ------------------------------
    Margaret Geiss-Mooney
    Costume/Textile Conservator in Private Practice
    Petaluma CA
    (707) 763-8694
    ------------------------------



  • 8.  RE: Mildew on leather

    Posted 06-03-2019 09:43
    Agree with the other suggestions made.  I wanted to note that you'll get a lot of advice about using products like glycerin, vinegar, mink oil, one-step, olive oil, neatsfoot oil, lederbalsam, or any of dozens of other treatments and dressings.  These are used - and have been used for probably hundreds of years - by those using leather products on a daily basis.  These products fit their needs - which are NOT generations-long preservation.  They need their leather to be supple and functional now, and act accordingly.

    I routinely ride in saddles with leather around 100 years old, but they were exceptionally high quality thick to start with, cared for, and need more maintenance than new saddles do.  In part because of routine use of products that swell the leather, then it dries again.  Point being, the advice most people will give you is right for THEM, not your needs.


    ------------------------------
    Jeannie Whited
    Museum Specialist, Collections Processing Unit
    Smithsonian National Air and Space Museum
    Chantilly VA
    (703) 572-4002
    ------------------------------



  • 9.  RE: Mildew on leather

    Posted 06-04-2019 10:13

    Hello All,

     

    After working with Marc at the Twain I spent some time brainstorming on and researching mold management in museums.  I highly recommend Mary-Lou Florian's Heritage Eaters, there are some comprehensive chapters on fungus. 

     

    I've thought about this a lot, done some reading, worked with moldy collections.  I've formed a couple of conclusions, which I'll go into below, but I would love to hear what other people think about managing mold in museums. 

     

    First, it seems clear that most if not all mold growth is enabled by an inviting habitat.  This means a food source and sufficient water.  Mold spores are everywhere; you can't just kill a colony and expect mold to not recur.  You have to provide an environment that does not deliver both food and water.  Of course many collections items ARE a food source, so we really need to focus on water.  In general, RH below 60% will prevent mold growth (watch out for microclimates, for example still air pockets next to exterior walls that get an RH boost from condensation).  Some molds can grow in more arid habitats.  It also seems that surfaces that have been disrupted or damaged are more inviting to mold.

     

    The other point is in dealing with existing colonies.  There are two distinct scenarios, which I am going to simplify by calling "active" (moist) and "inactive" (dry). 

     

    When a colony is active, it looks moist, it can cause staining, grow, "eat" surfaces, produce spores and make a smeary mess when you attempt to wipe it off.  In this stage, the colony can be killed or at least knocked back with chemicals such as isopropanol and hydrogen peroxide (don't ask me for recipes, I don't work with this option.) 

     

    When a colony is inactive, it will be dry and wispy in appearance.  There may be spores present but no new ones are being generated.  Essentially, this state is reached when sufficient moisture has been removed from the environment; the colony stops growing and protects itself with a sort of hibernation, waiting for moisture to return.  (I don't know exactly how dry you have to get the mold to inactivate it; it is likely well below 60%.)  In this state, the chemical treatments will not really be able to kill the colony.  BUT, now that the environment is dry and the colony is inactive, all you have to do is remove the dry remains of the colony (with adequate ventilation, extraction, PPE, etc., to prevent the spores from spreading everywhere and/or making people sick.)  If the RH rises again, those old colonies have been removed; in order for mold to grow again, new colonies will have to form from spores, which takes a LOT longer than an existing colony simply reactivating. 

     

    So essentially, the first step is to achieve a low enough RH to prevent growth and dry out the existing colonies; the second step is to remove all "inactive" colonies, to prevent rapid growth resumption if the RH spikes in the future. 

     

    I hope this helps and again, I'd love to hear others' thoughts on mold management in museums.

     

    Teresa Myers

    Objects Conservator

    Maine State Museum

    (207) 287-6659

    Teresa.Myers@Maine.gov

     






  • 10.  RE: Mildew on leather

    Posted 06-04-2019 18:55
    Here is another C2CC webinar resource for anyone who is would like to learn more about mold: https://www.connectingtocollections.org/moldrecording/

    ------------------------------
    Keara Teeter
    Graduate Fellow
    Winterthur/University of Delaware Program in Art Conservation
    ------------------------------



  • 11.  RE: Mildew on leather

    Posted 06-04-2019 18:56
    Jeannie
    I’m not entirely sure of your intent. But I think that there is a question here that is going unanswered. The classic musical instrument dilemma should it be played or just mutely observed? Are the books ever to be opened again? Is the upholstery ever to be sat upon? Are any of the leather/partially leather artifacts in question going to be required to demonstrate their original function of flexibility? If so the treatment may be different. Is there any real discussion of the science of leather conservation or has there been none? Is there truly no means to maintain flexibility in leather without shortening its overall life expectancy? What are the mechanisms of leather deterioration (functional and physical) beyond drying and becoming a food source for a bio organism?

    Charles A Phillips, AIA, AIC-pa

    433 Phillips Rd
    Nacogdoches, Tx 75964


    640 Brookstown Ave
    Winston Salem, NC 27101


    caparch@conservearchitecture.com
    336-918-3668

    From iPhone




  • 12.  RE: Mildew on leather

    Posted 06-05-2019 09:19

    Charles, my intent is to address the difference of advice between those USING old leather (as many horsemen do), and those PRESERVING old leather (as museums do).  Clearly, more than one person in this particular conversation has gotten the former, when they needed the latter.

     

    -Jeannie






  • 13.  RE: Mildew on leather

    Posted 06-05-2019 15:37
    Charles,

    I can not speak to books or other leather objects.  Most of my experience is with horse-drawn vehicles or upholstery.  Generally, when I examine the object, it long ago became stiff, brittle (often from red rot) and torn.  In all vehicles I have examined, the leather has one or more coatings applied to the exterior.  This was necessary as they were used in exterior environments.  It was common during the period of use to recoat vehicles every two to three years.  These aged coatings often contribute to the stiffness.  I am unaware of any non-disruptive treatment that can return "original" flexibility to the leather and still keep the historic materials, including coatings, intact.  If one exists, I would love to hear about it. 

    Marc

    ------------------------------
    Marc Williams
    President
    American Conservation Consortium, Ltd.
    acc@conservator.com
    ------------------------------



  • 14.  RE: Mildew on leather

    Posted 06-01-2019 12:38
    To follow up on the issue regarding mildew on leather, please refer to my previous C2C Care post on the baseball mitt thread.

    ------------------------------
    Keara Teeter
    Graduate Fellow, Class of 2019
    Winterthur/University of Delaware Program in Art Conservation
    ------------------------------



  • 15.  RE: Mildew on leather

    Posted 06-06-2019 22:29
    Hi Julie,

    When I read your post to Kathleen I was impressed with the care you showed when cleaning your leather object, from your first testing the vinegar in an out of the way place, using q-tips to control the work to your mention of allowing it to air-dry. So I looked up your Guardians of Eagle Point Museum website and saw your emblem with the great logo "Where memories find a home." 

    It reminded me of when I volunteered to assist my local historical society on a day when the daughter of an elderly resident brought in two shoe boxes of audio cassette tapes. Each tape had been carefully labeled and dated by the man I'll call George (I've forgotten his name which I guess makes my point about fleeting memory). Anyway George had recorded national and state political speeches such as the State of the Union by holding his recorder up to the radio. He told his daughter that when he died they should be donated to the society.

    To me the cassettes were useless. I was given to such harsh statements then because we were trying to develop a deaccessioning policy. And as I'm sure you know that can be brutal. But two elderly volunteers, Mary, a retired librarian and her lifelong friend Maureen, did not agree. (By the way, Maureen said she only volunteered to keep an eye on Marian). They knew George.  Had known him for over thirty years. They smiled and then laughed at the memory of how opinionated he was, how people would cross the street when they saw him coming. "Oh he was a character," They remembered a lot about George and his role in town meetings. It was clear to me the two shoeboxes had more value than I first saw. They were enduring keys that help to maintain the sometimes fleeting memories of a local community.

    It is a great thing you and your colleagues are doing to give a place for local memories.

    Best,

    Dennis


    Dennis PiechotaArchaeological Conservator
    Fiske Center for Archaeological Research
    UMass Boston
    Office: 617-287-6829


    ALTCONS Group Admin
    an Alternative Conservation Discussion

    ------------------------------
    Dennis Piechota OSX14.4.4/Safari12.1/Gmail/AppleMail12.4
    Archaeological Conservator
    UMass Boston, Fiske Center for Archaeological Research
    Boston MA
    (617) 287-6829
    https://groups.google.com/d/forum/altcons
    ------------------------------