Having a dead D4 key, I had to open up my Keylab and clean it. Upon reassembling the controller, I found that the key now works, but the white gooey glue substance (what is this for?) has stuck to the key. It's playable, but I have to "break it in" every time, and it's never as light as the other keys. This makes emotional playing hard, as there's suddenly a key that needs more finger strength to make sound.
What I'm wondering is if there's any way to clean the key without having to open up the Keylab, as it was a scary process I don't want to repeat unless absolutely necessary.