You probably also had the unfortunate experience of looking at your collection and finding brownish or reddish stains on the back of the stamps or on the stock book. Foxing affects stamps and other philatelic items, as well as books and papers in general. It is believed foxing is caused by a fungus group or maybe by the oxidation of metals contained in the paper. (Calvini et al, p. 365a)
I used to have this problem when I lived in Brazil but, although Swiss climate is quite helpful, I still come across foxing with time to time, especially when receiving new stamps (from collections that were clearly left long unattended).
To avoid losing your collection to foxing, a prevention method is to maintain environmental humidity to the minimum. It is also not advisable to smoke in the room where the collection is kept, since fungi enjoy the nicotine layer left over from smoking. Also, it is advisable to get rid of the contaminated stock books and albums. Don’t put wet stamps in albums, and try to keep stock books in shelves that can be closed, to protect them from dust. Opening the albums from time to time, to allow fresh air in, also helps. Don’t forget to separate the affected stamps from the others - to avoid cross-contamination.
There are many methods suggested online to stop or rescue stamps from foxing, such as submerging the stamp in boiling water (see results in the picture above), or hydrogen peroxide. I have never tried the latter, but must say hot water can affect stamp colours, depending on the stamp (please see the illustration bellow). Furthermore, it does not fully solve the issue. A ‘cure’ for the affected stamps is debatable. I have read in an article by Guy Podevin in the Brazilian Philatelic Club’s website that it is possible to eliminate or at least lessen the damage by foxing by submerging the affected stamp in a mix of 20-30% lixivium and water, leaving it for some minutes, then put them under pure water and let it dry. This will of course, take out the gum of new stamps. The author, however, suggests that instead of putting it under water afterwards, that one may put them in tichloroethylene and the gum will be safe.
I am a bit skeptical with using chemicals to treat foxing, since this could be parallel to restoration: which is a very criticized topic in philately. Unlike art, restoration is seen by many philatelists as taking out the originality of the item. Of course, stamps that show stains lose a lot of their value, but sometimes restoration may take out all its value.
I should note, however, I've also come around the term 'tropicalization' and this should be distinguished from 'foxing'. Tropicalization does not contaminate others, usually appearing on the edges of the stamps at first, and are visible on both sides of the paper. This problem is less alarming in the sense that it does not spread to others, and can be contained by reduced humidity levels and temperatures.
In the end of the day, it is up to the collector if he/she wishes to try and ‘fix’ the issue or simply throw the stamp away. What do you think?
•Calvivi, P., , Ferroni,A. , Mariotti M.G., Zotti, M. “Chemical and Biological Foxing on Historical Papers” in 5th International Congress on ‘Science and Technology for the safeguard of Cultural Heritage in the Mediterranean Basin’ (2011) by Ferrari, A. Alpaslan Hamdi Kuzucuoglu, Istambul University: Turkey.
•Podevin, G. Ferrugem!? Disseram Ferrugem? [online]. In www.clubefilatelicodobrasil.com.br , accessed in March 12, 2013.
Update from 14.08.2016:
All pictures in this website were taken by and are property of the author. The exceptions are properly and visibly cited.
Please do not use pictures from this site without the proper citation or the author's express authorization.
All posts and pictures in this website are property of the author.