Re: Do soda cans have liners?

Yes they do!  Soft drink cans are lined with an epoxy resin to prevent the
beverage from "eating" through the aluminum can.  The liner is sprayed
into the interior of the can and then baked to set the resin.  Liners help
not only protect the can from the acid in the soda, but also protects the
soda flavor from reacting with the metal.  Damage to the liner can occur
from denting of the can during manufacture or distribution and significantly
shortens the shelf-life of the soda.  Some beverages require thicker liners
than others because their composition is considered more "aggressive"
and they tend to react more easily and violently with the aluminum.

I hope this info has helped you with your project.  You can always email me 
if you need more gorey details.

Kieran