I have an expired Oyster Travel card for London, but it still has money in it. Can I still use it?

Oystercards don't expire. If it had a Travelcard on it, then THAT has expired, but if you put money on it as well for "pay as you go", that hasn't and you can still use it.

No such thing as an expired OysterCard.

If its expired no

No. It's expired.