a credit union.
**
elbows** idea to send it back gave me a good idea. I am going to send it back, but I’ll ask that they send me a new Oyster card (I had asked that they refund the price of the defective card which they neglected to do, it should have been £18.20) with the amount on it.
I’ll probably be going back to the UK, or someone I know will. win/win!
Do you think it will work?
I think that’s a brilliant solution. Do consider that such cards change formats frequently, you need to be sure it will get used within a reasonable timeframe, I’d think.
Frame it and sell it as a curiosity.
Until you’re on a plane, somewhere over the Atlanic, and… doh! 
I don’t know about credit unions cuz they’re small, but there is a difference between my bank won’t take it and my branch won’t take it. Smaller stores may not be equipped.
The ATM idea might be worth a try. This is a big suggestion, but maybe if you opened an online bank account, you could mail it to them. Probably way more work that you want for 20 bucks, but it is pretty painless of a process.