Like a fire extinguisher...everybody has one...nobody has every used one...

You can apparently ground ship the butane mix fuel canisters within the contiguous states

https://adventuresinstoving.blogspot.com/2011/11/can-i-mail-backpacking-gas-canisters.html

You have to mark it "Otherwise Restricted Material – Domestic" (ORM-D) and package it appropriately.  I have not tried this.

I think the same applies for Bear Spray...which you may also be able to ship UPS ground with the same marking. 

Not sure if it is worth shipping or shipping back and there needs to be a post office or if appropriate a UPS store near your destination...but that is a different matter.

You definitely cannot fly with either in the US.