Basically what it says on the tin.

I am about to embark on a huge and terrifying purge of my belongings, in part because I need to have less stuff (because reasons), in part because I need to have more money (because related reasons). One of the things I have a startling supply of is BPAL (Black Phoenix Alchemy Lab) perfume.

Does anyone know, from "I have done it and here's how" experience, how to mail perfume/essential oil within the US? I've found both "it's a hazardous material and you can't" and "it's possible, just hard." Well, I need to know how.

Help?