I'd take it back to the store, tell them what happened and see what they do. As long as you are honest about the situation, you are not ripping off the store.
I had a somewhat similar circumstance with a trailer winch, purchased from Academy Sports. I bought it along with a bunch of other stuff and accidentally left it in the shopping cart, while putting the rest of the stuff in my car.
I returned to the store after realizing what I had done, but the cart wasn't where I had left it in the lot, nor was there a winch in any cart that I could see. I didn't actually go into the store looking for a free replacement (my intent was only to ask if they had found one), but they gave me another anyway. It was about a $50 winch, which probably cost the store half that amount.
My personal opinion is that the store manager made a very good decision. I was actually somewhat new to Academy Sports at the time and now shop there frequently. I have surely provided them with a great deal more profit, than the $25 bucks that they lost by being nice. Simply put, in this age of retailers who treat customers like crap, I am very happy to spend my dollars at a place like Academy - as I am to tell everyone who wants to listen, about them.
I do agree with all those who suggested that you not try to repair it. Risking a chemical burn and all sorts of other mayhem, just isn't worth 70 bucks to replace it, if you have to lay the money out.
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