Copy paste a reddit post:
Be careful, this is very dangerous and it's important to weigh the odds. Here's all I know, I hope it's helpful and be sure to double check. I wouldn't want any misinformation to jeopardize someone else's security.
Use the United States Postal Service (USPS) instead of a private company. Since USPS is a government organization a search warrant is needed to open your package - it isn't with private companies.
Use gloves the entire time and switch them for clean ones with each layer of vacuum sealing. Vacuum seal it in an air-tight bag. This isn't enough to safely evade drug dogs, so seal that in a turkey bag (special kind of bag with deodorizing crystals). Do a few more layers of vacuum packing on top of that, maybe even another turkey bag, and ship according to size. There are varying ideas on how to actually ship so you may want to look into that and brainstorm something that works for you.
The main point though is vacuum sealing and using deodorizing bags that actually trap/neutralize any smell. Think about containing smell as well as weight...just try and have the weight of the package and its contents make sense.
