I believe you can donate them to charity. Try this
Donate Airmiles - LoveToKnow Charity or similar.
I feel the same about BA after they treated us with total contempt some years ago and compounded the situation by lying about what had actually happened when the dispute was escalated. I also had a lot of IB miles, and that's another airline I hope never to set foot on again. I was able to use my IB miles to send my mother in law on holiday!