How do you protect LTO media shipped offsite to Iron Mountain?

We currently ship all backupsets offsite to Iron Mountain
on 3590 J cartridges w/ no noticeable problems; we just pack
as many tapes as will fit tightly into one of Iron Mountain's
metal shipping cases.

We've been told that LTO cartridges are much more susceptible
to damage and have never ejected or shipped any of them offsite.

I'm thinking any ejected LTO tapes should at least be put back
into their original plastic cases before being packed (how?)
into a Iron Mountain shipping case, but what do you do?

Have you had any problems shipping LTO tapes offsite?
Thanks for sharing your experience and advice.
--
Jim.Owen AT Yale DOT Edu   (203.432.6693)