konichiwa!~

well, i always am worried about cels being 
damaged in the mail, especially when buyers do 
not purchase insurance.  the way i package my 
cels is to put each item - cel, sketch, douga - 
in separate folders, those stiff priority mail 
envelopes, then place those inside of the 
slightly larger paper envelopes, seal it, and put 
it in the priority mail box.  after that i NEVER 
close the box with the sticky stuff on the 
inside, but instead use priority mail tape on 
both open ends of the box, and then on the 
outside of the box on each side to seal it 
fully.  this method has worked for me for a long 
time, and your buyer can just pull the tab on the 
box to open it and easily slide the package with 
the cels in it right out.  hope that helps you 
for future dealings,

haruna