strange the link was working few hours ago. this one should work: http://bookos.org/dl/1174511/2a3b2b

John benedict i know water is to be avoided. As i said in a previous post few weeks ago the worst problem is lunette collapsing and kindly person from pch.gc.ca explained me it's cellulose acetate which is confirmed by vinegar odor released.
She told me nothing new to protect plaques: temperature stabilized ~ 18°C, avoid humidity, don't let plaques touch each other, etc
She added that that active charcoal in unecessairy because to be useful it must be change (or regenerated) often.

For me, i recently tested a wine service box but hydrometry wasn't controlled. i'm 1/2 serious when i'm talking about a lab incubator ... it's near the best solution ?

I must add i asked french association numismatic, they don't know the answer to preserve plaques...
i think if i have opportunity one day i will ask directly to mcc casino! as they have plaques of 50 years in excellent condition they must have some tricks.

I'm also thinking about test silicon spray on plaque but as i read in some article about plastic conservation it's hard to forsee long term effects of interaction with plastic protectors.
sometimes i feel depressed when i saw no progress on this subject