[Juju]

I will start by saying I have never handled or worked with dry ice before, so forgive me if I am overlooking some things.

No problem at all.

in my head this is how it plays out..... I weigh just over 2kgs of dry ice and place it in the box, my local post office is less than 2 mins from my home, so within 5 minutes of packaging the ice I can have it weighed and logged in at a post office. does this seem viable or am I missing something.

What about calculating storage and transit time?

The last thing you need, Is for the company to receive your return with a portion of dry Ice.

from what I understand, it can take 24 hours for 5 pounds of dry ice to sublimate?
so given that I maybe drop the box off at my post office in the morning knowing that it won't be collected until the evening and then at the very earliest it would be delivered the following morning back to the warehouse, this in my mind leaves enough time for the dry ice to evaporate.

sound like a viable plan or am I still missing something?

also am I right in saying that the box only needs to weigh the correct amount at the time of returning it to the post office right?