[QUOTE=brujaja]
… what constitutes packaging that will allow CO2 vapor to dissipate? Would cardboard covered in brown paper be OK?
[/QUOTE]
Just a cardboard box. No paper.
A regular box isn’t air tight - they just don’t want people doing something goofy like putting the dry ice in a sealed jar, can, or plastic bag as those will eventually burst.
Wrapping packages in paper is never a good idea as it invariably gets snagged on a belt at the sort facility and your box is now naked with no address.
You can pack things into a soft side cooler with ice packs. If it’s something you can freeze, like a large bowl of soup, freeze it, pack it tightly in an insulated container, and ship it.
You want to avoid any air space inside your container, so use a soft container, squeeze out all the air, and pack it into a larger rigid container and stuff it with foam or crunched up newspaper.
If you can get dry ice packs you may as well use those.