Hi,
I have some 19th century German and Austrian stamps. The stamps were in an old German stamp book. I have read that the gum used on these stamps will deteriorate the stamp, which it has. I have removed the gum, but some of the stamps are hard after soaking in distilled water. Has anyone used a product like Archival Mist Spray at link
http://www.pfile.com/product/c-am-5 If so, did it seem to make a difference or do you have any other suggestions. Thanks.