Where the heck do I return them or do with them? 

there is a recycling center off to the side of ralphs on oceanside blvd where you can recycle them and get cash back....its not a whole lot but better than nothing 

There's also one at the very end of Mission Avenue in the industrial area, down by airport road. 

go out the fallbrook gate, make the first left, then immediate half right, its down a bit on the right. 

Thank you. 

These guys have several locations:

RePlanet recycling stations