Sure, but why work that hard? Instead of trying to make a form-fitting rubber (or other di-electric) liner, just wrap the items you want to protect.
Let’s say it’s a handcrank radio/flashlight. Wrap it loosely in brown Kraft paper, tape it loosely with ‘scotch tape’, then wrap it again in some bubble wrap, then place it in the ammo can with other devices similarly separately wrapped, SEAL the lid well from a gap standpoint, and you are good to go!
Indeed the idea is to have real current flow through the can to the ground, and static electricity to stay on the outside of the can and flow to ground.
Thanks for the info!