Has anyone figured out the magic packaging and words to say to the usps counter to get your Lippo batteries to go through the mail?

I've scrolled around the usps web site enough to know how confusing and convoluted it is. Seems the average counter person at usps can't figure it out either.

I know they have to be labled lithium and ground only. Is that all there is to it?

Thanks,
Motorman