I wrote to a friend who repairs oboes and English horns (among other things), and he suggested I try to clean the key with alcohol. If that didn’t work, he suggested first cleaning and then possibly taking the cork off the little lever that pushes the B key down (yes, I will deal with the second finger, left hand key being called that now that he’s explained it!). Voila! It works. When I took that part of the horn apart, I could see that the cork had a spot in it that was so far gone that the piece of metal sticking out from the B key would stick to it, and since the spring isn’t as strong as the key (or some such thing), it stayed down, rather than going up. Piece ‘o cake to fix, although I’ll probably get new cork on at some point. But thanks Bob! I’ll make it through Nutcracker without too much trouble now.

Maybe.