Yes, I think that the plastic cases that are 
available in Japan are the best all around. 
They are light but resilient.  They are cheap, 
see-through, and you could actually keep your 
cel in one of these and use the case over 
again! No need to throw anything away. They 
can be recycled for your own next cel sale.
I have used them countless times. Although, I 
agree with the last post, in that, they will crack 
on the edges if something slams down on 
them. but even then it is rare and I have never 
heard of the end cracking damaging the cel. I 
usually use, (if I have the supply) bubble wrap 
in the inside of the box, to make an excellent 
buffer. Regular sized cels fit perfectly (A-4) in 
the case (B-4), but larger (theatrical sized ) 
cels barely fit, so those are a little risky. I f 
anyone really wants some in volume of not 
less than 10 . I don`t know if the postage 
would be worth it to you or not  to send them to 
you though!  Anyhow, LMK and I can see what I 
can do ^-^.
E.