[Rodney]

I would imagine you guys would neatly fold the tshirt in such a way before sliding it into the envelope, but im wondering, if its a cardboard envelope... what happens if it gets wet in the rain? Wouldnt you have to wrap the tshirt in some kind of plastic wrap before putting it into the cardboard envelope.

I just shipped some shirts to Australia and I used a weather resistent type polybag container. But the tyvek envelopes are also pretty weather resistant.

Inside of the shipping container, the shirts were folded and bagged (the bag was sealed).

I don't think most people use cardboard style boxes without some sort of inner protection.