I know your horror- but mine was completely 
damaged.  I had bought some VERY expensive 
original production art from Warner Brothers.  To 
my horror, I found it stuffed in my mailbox, 
folded 3 TIMES over.  I was mortified.  The 
contents- the production sketches, animator's 
notes, and cels- were completely damaged and 
destroyed.  

From then, I have ALWAYS paid extra to have my 
cels actually mailed in boxes in order to 
discourage the mailing morons from folding more 
of my packages and destroying their contents.