question about shipping lipos..

[DwightSchrute]

i've read that lipos aren't supposed to be left in cars, etc during the summer due to the heat.

can't they become dangerous if left is such heat?

i was thinking about selling some lipos and buying some more, but i'm concerned about the storage in shipping. how does it work in transit if most companies just use priority mail or first class mail?

do they classify it as hazardous materials?

any help is greatly appreciated.