We occasionally receive questions at the American Philatelic Research Library about what someone can do to take the best care of their stamps or how to clean them. The answer falls under the umbrella of preservation and conservation.
As librarians and library workers we have some general knowledge about the topic but aren’t necessarily specialists. Our approach would usually be to check what the various books and articles in our library have to say, but there’s just one problem. Preservation and conservation are ever-evolving fields of knowledge. What was true (or safe) a decade ago may not be so today. There are plenty of articles going back almost a century on the topic, but how many of those recommendations are still valid?
Collectively, preservation and conservation are a set of practices based in chemistry – how various materials interact over time – but what is the difference between these terms?
Preservation (or preventative conservation) is passive: doing what you can to keep what you already have as close to its current state as possible. This includes making sure items are safe from external forces and slowing decay as much as possible. Paper wants to turn to dust and will eventually do that with or without your help, but you might be able to control how quickly it happens.
Conservation is what happens when you want to make what you have better, which can include stabilizing a fragile object and cleaning.
This article will be about preservation, not conservation, because it is incredibly easy to ruin the thing you wanted to save in the first place by starting with the intention of “just cleaning” to actually changing the nature of the object.
Preservation and conservation have been discussed together so often that even the best articles tend to include something on the latter, but the references I recommend here are for preventative actions alone. Once part of your collection is already dirty, damaged, fragile, or otherwise needs help, ask a conservator. Beyond the likelihood of ruining a high-value item, a significant number of books and articles published in various philatelic journals over the years recommended treatments and storage options now known to be extremely dangerous to both collections and their collectors. If you take away nothing else from this article, if you see any recommendation that sounds like a chemistry project, please ask a professional first!
"Once part of your collection is already dirty, damaged, fragile, or otherwise needs help, ask a conservator."
I will also be focusing exclusively on the care and handling of printed paper. Most stamps, covers, and documents will fall under this category, but know that art, photographs, film, plastics, metal, and fabric all have their own storage and handling requirements. A good resource for a wide range of materials including paper and philatelic items is Saving Stuff: How to Care for and Preserve Your Collectibles, Heirlooms, and Other Prized Possessions by Don Williams and Louisa Jaggar (APRL call number HE6184 .P933 W721s 2005). Chapters 1 and 11 are the most relevant for philatelists. It also manages to stay away from the technical jargon that bogs down most other references. More advanced information is available from the American Institute for Conservation’s (AIC) page on Caring for Your Treasures (https://www.culturalheritage.org/about-conservation/caring-for-your-treasures) and the Northeast Document Conservation Center (NEDCC) (https://www.nedcc.org/free-resources/overview).
Finally, this is meant as an overview and general guide. The technical details of anything discussed here, including why some paper lasts longer than others and specific humidity and temperature guidelines, can be found elsewhere, including the AIC and NEDCC mentioned above and previous articles in The American Philatelist (March 1979, Volume 93, No. 3). Consider this article a starting point.
Left: Humidity caused the gum on this stamp to activate and damage the face of the stamp lying beneath it. Right: Humidity can also cause curling.
Paper and photographic collections are sensitive to humidity and temperature fluctuations, so it is best to keep them far from heaters, radiators, humidifiers, air conditioning vents, and pipes. Moisture and humidity lead to mold, paper curling, and gum cracking, while heat and dry air make paper brittle and more prone to tearing.
There are a number of issues intrinsic to philatelic collections that invite pests, including potential nest material and food, but the risks greatly decrease if you keep storage and work areas clean and do not eat meals or snacks in the same room. If you smoke or burn candles, do not do it around your items; nicotine and other additives will discolor them, the smoke deposits are nearly impossible to remove (let alone the smell), and some past treatments and watermark fluids were extremely flammable and there may be some residue.
For all of these reasons, do not store items you care about in attics, basements, garages, outbuildings, or warehouses. No one likes to think about disaster prevention or severe weather, but basements do flood and attics leak.
In general, if you think a room is comfortable, your items will as well. Keeping your collections in an area you visit frequently makes it more likely you will notice any problems when they start, rather than weeks or months later.
Tape damage on a cover. (Image courtesy of Jasmine Smith.)
Most light causes permanent fading and color shift. Purples go brown, black fades to red, and red goes orange. Keep this in mind when choosing what and how to display items in your collection, whether exhibiting or at home. Keep the lights off and shades drawn when you are not in the room. UV-protective film can block some of the worst spectrum from windows while still allowing some natural light.
Museums will regularly rotate items on display to avoid significant damage; so should you. Blue wool strips, or blue scale fading cards, are a good test of whether you should worry about light levels in your workspace and display area. These are available from Gaylord Archival (gaylord.com) among other suppliers.
Avoid handling items as much as possible. If you must, use tongs for stamps but do not hold them tightly enough to cause a dent or crease. Clean, bare hands are better than gloves unless you are handling photographs or plastic items. You will have significantly more feeling and understanding of force with bare skin, and gloves are more likely to snag and accidentally cause a tear or crease.
Keep folded items flat and do not create new folds. A fold is a weak point, and a piece of paper will eventually tear or break along that point. If a document (journal, letter, etc.) has been folded and is now brittle, do not try to unfold it.
Handle larger documents or sheets carefully, with both hands; transport them with support (on another, larger sheet of paper) if they must be moved. Also consider the weight of the document or sheet; examine it on a flat surface and do not hold it like a newspaper.
Do not use adhesive tape of any kind for repairs, whether Scotch, masking, or packing tape. The glue will bond with the paper over time and discolor and darken it in the process. The resulting stain is nearly impossible to remove. If left long enough the attachment will fail, the paper will turn translucent, and it will be so dark you won’t be able to read what was written on it in the first place. Lamination will do the same on a larger scale.
Do not use paperclips, binder clips, or staples. All paperclips bend the paper they keep together and metal clips and staples rust over time.
Left: A dark line on the front of this stamp and the brown stain on the back are evidence of old adhesive tape. Right: Paper tearing at the folds. (Image courtesy of Jasmine Smith.)
Look for items labeled (in order of preference) acid free, lignin-free, buffered, or archival. None of these terms have any legal significance, but “archival” is the least descriptive and most easily abused by manufacturers. Technically you can put anything in an archive that you want, whether it would actually protect items or not. Also, what begins as “acid free” tends to lose that property over time and will need to be replaced. Do not keep items in glassine envelopes long-term; the ones from Gaylord Archival (gaylord.com) include the warning “pH will drop over time; do not use for long-term storage and replace when Glassine takes on an aged appearance.” Gaylord is a good supplier for archival-quality storage and retrieves a number of results if you search for “stamps.”
For plastics, currently the best is polyester (Mylar or Melinex). Vinyl and PVC will stick and transfer print over time.
Many albums do not include information about what paper, plastic, or adhesives were used in their construction. If plastic seems yellow, tacky or sticky, warped, brittle, or melted; or the paper is changing color (usually yellowing), foxed, or transferring color (dark brown or any of the object’s color), think about switching to another album, interleaving pages with acid-free paper, or using a different storage method altogether.
Did you know that snails can be a problem for your collection? I didn’t! There have been excellent articles already published on what bugs and other pests can do to a collection so I will cite them and ask that you visit The American Philatelist on the APRL’s Digital Library to learn more.
Weststrate, David F. (September 1984). "Warning: Your Collection May Be Bugged." The American Philatelist, 98:9, pp. 929-932
Berlin, Steven J. (September 2013). "What's Eating Your Mail." The American Philatelist, 127:9, pp. 830-840
Berlin, Steve. (September 2018). "What's Eating Your Mail?" The American Philatelist, 132:9, pp. 850-858
For more details about best practices for storage, please see Gaylord Archival’s Guide to Collections Care, available to download from its website (https://www.gaylord.com/resources/guide-to-collections-care). Additional options for philatelic material are also given in Saving Stuff.
Foxing (or foxed) describes the presence of small brown dots or stains on paper. This example is mild, but the stains can be large and obscure text and images. Theories on the cause include oxidation of impurities in the paper and some type of microorganism.
Examples of damage from handling. Brittle paper and gum cause breakage at a fold. Aggressive removal from an album can cause tearing.
What we know about this subject is always evolving and each book and article tries to make the best recommendations for its time. I aimed to do the same, but what I write here might not be the case a decade from now.
Remember that perfection is the enemy of the good. The book I mentioned earlier, Saving Stuff, explains what you can do for different levels of protection. The highest level would be to keep everything in a perfectly controlled dark room and never see or touch it again, but then you wouldn’t actually get to enjoy your collection. A little prevention goes a long way: if you are careful the items in your care can last a very long time, but neglect will lead to disaster.
Smith, Jasmine. “Think like an archivist: preserving postal history collections at home.” YouTube, uploaded by American Philatelic Society, December 12, 2020, https://youtu.be/kyj_Kxwebzk.
Kindley, A.D. “Medical hazards in philately,” London Philatelist 89 (May/June 1980)
Thomas O. Taylor, “Protective plastic films in philately: how do we find ‘the right stuff’?” The American Philatelist 102 (March 1988)
The Stamp Restorer. “Preservation Guidelines.” https://www.thestamprestorer.com/philatelic-preservation.
Smithsonian National Postal Museum. “Preservation.” https://postalmuseum.si.edu/preservation.