Let it dry out thoroughly before you oil it.

I nearly ruined a tenor recorder by not playing it in properly. I thought I had done so, but I hadn't and used over a long period one day. After a time the top notes would not speak properly. I rested it and played a plastic one for a while and it recovered, but was not quite the same. Play it for too long and the top notes (usually top A and above) would not speak cleanly. I recently sent it for revoicing and that seems to have resolved the problem - I hope