Hey, James. Actually, I’m posting at the forum. You’re getting them in email because you’ve subscribed to the thread I guess. I’m taking mine apart for cleaning and deodorizing, but I’m not planning to remove any keys. However, with the back cover off and the reed plates away from you, you’ll see the row of springs. Remove the spring from the key you want to work on, and I think you can wobble/pull/push/work the key out. I’ve removed the reed plates from mine and found part of what looks like white key material and some excess flashing from the manufacturing process. I’m going to clean it with Dawn dish detergent.
Looks like the airflow, again from the springs end facing you, is from the mouthpiece, through the channel all the way to other end, into the valve compartment from the treble end.
My leak is somewhere in there. The clue is that the leak is under the keys, so it’s either a pallet valve not sealing, or the gasket between the compartments (on the back cover) is letting air flow over.