On Sat, 3 Dec 2016, drlegendre . wrote: There are numerous black foam formulations. I inherited some lenses (including a Leitz Tele-Elmarit 180mm (<250 made)) that had been stored for a few decades in an essentially airtight case with black foam. When I first opened the case, it seemed as though there was liquid in the case, with an intense vinegar? smell. Second time that I opened the case, a few hours later, it was dry and crumbly, and the outer painted surfaces of the lenses were badly pitted and had to scrape bits of the foam off, but NOT at all like water damage. It turned that lens from mint condition and a major rarity, into usable but POOR cosmetic condition (a loss of more than a thousand dollars in value!). (Three other cases had simply disappeared between the time my buddy died and the time that the county let us go through the house.)