I'm really sorry, I got busy and forgot about this thread! This is how I ship BTS. It may not be useful to people outside of the U.S., but this is the only place I have shipped from. This is also assuming that I am shipping while the weather does not require a heat pack or a cold pack. If you do need one of these, it is very simple. You just activate them according to the instructions on them and tape them to the top of the box (on the inside).
I use
www.shipyourreptiles.com. I am not affiliated with them in any way, but I have had very good service from them, and never an issue with an animal arriving safely. They just switched this year from UPS to FedEx though, and I have only used them once since then. You can buy shipping supplies on their website, which I would also recommend. You can get a complete "kit" to ship just one animal which is very convenient, but of course if you purchase larger quantities the cost will be lower per animal shipped.
Here is what you need to ship a skink.
Items include a sturdy box w/ styrofoam insulation and a reptile bag. I use shredded paper or packing peanuts as cushion.
First you assemble the box.
Then cover the bottom with the paper, peanuts, or other material to keep the skink from bouncing around inside the box.
Next, I wad up some paper towels and put them inside the reptile bag. This is to absorb anything that might "come out" of the skink during transport.
After that, it's time to put the skink in the bag.

That is never fun, but the truth is if you do all of this right before you drop the package off, and you drop the package off at the end of the day, the skink will be just fine for the short time that he is in the box.
Then securely tie the bag closed. I use a small zip-tie just to make sure it doesn't come undone.
Next you put the bag into the box and fill the empty space with more peanuts, etc.
Tape the box securely closed, and it is ready for a label. I poke holes in the box for air, but that is really not necessary. The box is not air-tight, and the skink won't be in it too long.
You can pay for the shipping and print out a label right on the shipyourreptiles website. After you print out the label, just tape it on the box and drop it off at any FedEx location. Be sure to NOT tape the label over a seam in the box though. During transport the boxes move around and rub on each other. If the address or bar code is over a crease, it will sometimes get rubbed off. This is what I mean.
This is BAD;
This is GOOD;
I have packed dozens of animals this way, and I have never had one not get to its destination safely. I hope that is helpful.