I must agree... I have many of my cels framed and 
have had no problems with them. After doing a 
little homework and from experience, framing 
offers the best protection and display value. I 
believe in this so much that on some of my higher 
end cels I'm spending around 100 dollars per lite 
for true museum glass!! Just remember to use only 
rag mats, 100% acid free materials, and an UV  
glass and it should be fine. Stay away from 
the "acid free" buffered stuff because it will 
turn acidic after time.  Remember too, that other 
environmental conditions such as humidity and 
temperature fluxes can cause cel deterioration as 
well, no matter how well a cel is framed. So do 
your best to keep your cels "comfortable."

Regards,
"Admiral" K Neal