Cleaning Native Leather In Use?

January 29, 2018

0B36C027-6E3D-4D9E-8466-4CC46E728E8AThis beaded leather Athabascan vest is the subject of a recent question to the Alaska State Museum: tribal members want to know how to clean leather. The tribe is conducting interviews with members to record the meanings and origins of important regalia and taking photographs. This vest is the Chief’s vest, and still in active use. The tribe does not have a large number of cultural heritage pieces, making it rare and important. Elders still wear items of regalia like this, and some elders may “take them on their journey at their end of this life.” The Cultural Program Manager for the village traditional council is wondering how the normal soiling from years of use might be cleaned, and how they might provide ongoing care for things like this.  We need to take into consideration museum care standards but also the cultural need to continue using the vest.

I love this question because we are hearing it more and more at the Alaska State Museum…how to support the care of objects in active cultural use? On the one hand, there are commercial products that might reduce some of the stains seen here, but those chemicals might shorten the longevity of the leather. Proprietary commercial products often contain extra chemicals that are not useful and can be harmful, and the strength of the active ingredients can be much more harsh than we would use in a museum setting. In the museum setting, the prevention protocols would be very strict and we’d be aiming to preserve this vest for around 500 years.


I’m not certain the exact leather technology we are seeing in the photo, but if I had to guess I would think perhaps a Native-tanned moosehide (perhaps similar to the technique currently being collaboratively studied at the Anchorage Museum…keep an eye out for the report on that project). The thickness, color, and Athabascan origin make me think it might be moosehide. You can see a fuzzy suede-like layer on the front of the vest, and a grain layer on the interior of the vest. If a leather is flexible, everything but the grain layer is like a felted tangle of collagen (skin protein) fibers. The grain layer is the layer that had the fur…the layer we typically see on the outside of a motorcycle jacket or baseball glove. Some Native-tanned leathers have the grain layer removed. But behind the grain is that felt-like tangle. The suede-like part. The flexibility of leather is maintained by the tanning process which lubricated the fibers to prevent them from binding up with each other. This happens BEFORE the leather is dried, which is part of why WE DON’T USE LEATHER DRESSINGS:

Here’s the tricky part…the cleaning techniques conservators like to use on leather are usually done dry (things like vacuuming, the dry use of soot sponges or urethane sponges, gentle cleaning with unvulcanized rubber such as Groom/Stick or vinyl such as a white eraser…) These can be a little bit abrasive, pull up fibers, or deposit crumbs of the cleaning sponge in the structure of the leather, but it is hard to cause serious damage with those techniques. Unfortunately, those techniques don’t tend to get rid of greasy soiling, such as from body oils, sweat, or food residues. In order to remove that kind of soiling, conservators might turn to wet techniques (distilled water with various substances added to enhance cleaning, detergents, solvents etc). But the danger in going with wet cleaning is that the things intentionally put in the leather during its manufacture that keep it supple and soft can ALSO be cleaned right out or moved around by wet techniques. This can result in stiff, shrunken, darkened, or distorted leather. It could also cause the stains to simply move around or go deeper into the leather and not actually come out.   In other words, the kind of aggressive techniques needed to make stains like that come out might actually make things worse. Museums often accept a certain level of use-related staining as part of the object’s history. This might not be appropriate for ongoing cultural purposes.

I put this posting out on the blog here to stimulate discussion about the risks and possibilities for cleaning and caring for this kind of item. It is more precious and special than most of the things in our closets at home, but it is also unreasonable to expect museum-level protection for something that is still in active service. I think where we are headed is for folks with museum expertise to provide as much USEFUL information as possible to the folks tasked with caring for these items, and empower them to pursue the kinds of solutions that work in their communities. I’ll provide an update to this post when the conversation has gone further…

UPDATE 2/3/2017:

I asked others in the objects conservation profession for ideas on this cleaning dilemma, and as usual my colleagues were very generous with their knowledge and advice. Choices for cleaning this vest include a wide range of options, each with pros and cons. On the most conservative end of the spectrum is the possibility of doing nothing, and accepting the “wear polishing” as a confirmation of the history, heritage, and authenticity of the garment. Next gentlest is the use of relatively crumb-free cleaners used dry, such as white foam cosmetic sponges, or “soot” sponges marketed under such names as Absorene, Smoke-off, and Gonzo. Sometimes soot sponges (vulcanized rubber sponges) do leave some crumbs, but they are often sizeable and easy to vacuum off. Someone suggested there might be risk of removing or reducing possible smoke tanning in the leather with a soot sponge. Dry, powdery cleaners were also suggested for soaking up the oily staining: warm dry cornmeal, baking soda, corn flour, Fuller’s Earth, or powdered erasers were mentioned. Any of those would then need to be removed from the surface, and might be difficult to remove entirely or might leave a residue. For example, corn flour might leave a scum of corn oil? A thin absorbent tissue in between might reduce the residue transfer, but might also block absorptive action. Removing the powdered cleaners might be trickier than expected, and enough suction to remove the powder could also remove some leather fibers. Somewhat more aggressive is the suggestion that roughing up the surface to scatter the light might help the stain look lighter, even if it did not go away. For example, gently rubbing the surface in a rotary motion with a paintbrush, or even micro-abrading the surface with a scalpel under a binocular microscope. On the most aggressive end of the spectrum were techniques that might use petroleum distillates such as Naptha or white spirit to dissolve the oil, or other water/detergent or solvent-based cleaning options. There were even suggestions of solvent cleaning mixed with lecithin to replace fats that might be pulled from the leather by solvents. Oily substances are both a stain component but also a natural part of the leather. The “wet” cleaning techniques offer the highest risk for damage in the form of stain movement, tidelines, stiffening of the leather, matting of the surface, or other undesirable effects. The wet techniques are most likely to give dramatic results, but come with the most dramatic risks too. Anything attempted along those lines (or the use of commercially available leather cleaners) should perhaps start with a really tiny area inside the pocket? Testing inside the pocket is a good idea with any technique. What this all comes down to is the ultimate goal the community has for the cleaning of this vest, and comfort caretakers have for the risks. Museums can share the ideas and techniques used in the conservation lab, but my goal is to make an object last for 500 years and that might not be the purpose of this particular vest. One final thought …investment is often made in retaining skills, relationships, and knowledge about technologies so new beaded leather vests can be made, too. There are Athabascan beaders and skin sewers who know how to make new vests, and this is a complementary preservation technique too. Thank you to everyone who shared in this conversation! I hope to post another update later on…