Black anti-static foam corrosion

[COURYHOUSE at aol.com]

let me know if you have a 90 mm summacron  f2(?)
a nice  working one  is  great!   I not  good  inside but looks ok on the 
outside let me know... we need it to go on an M2 in a  display.
 
Ed#  _www.smecc.org_ (http://www.smecc.org)  
 
 
 
 
In a message dated 12/3/2016 8:24:48 P.M. US Mountain Standard Time,  
cisin at xenosoft.com writes:

On Sat,  3 Dec 2016, drlegendre . wrote:
> Interesting find, thanks for posting  this. I've seen this as well. with a
> batch of old ICs which had been  stored (in black foam) for some 20-30
> years. The leads kind of just  stayed behind in the foam..
> My assumption was that the foam was simply  hygroscopic, and held enough
> atmospheric moisture & pollutants to  foster corrosion.

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.)