Posted in hopes that it’ll help someone somewhere:
A while ago, I spilled lemonade on my N810’s keyboard, then accidentally closed it before I could wipe it clean. I did what I could, but over the following days, the keyboard increasingly started making squeaking and crunching sounds. So I thought I’d take it apart to see if I could clean it.
It turns out that the keyboard just comes off. If you raise the stand bar (the one you need to raise to insert an SD card or open the battery cover), you’ll see three holes in the front (four, actually: the smaller one is the microphone). The three holes hold hooks that hold the keyboard in place.
Slide out the keyboard, and use a small screwdriver to push the hooks in. Lift the keyboard up a bit, and then pull it out. You’ll be left with the metallic keycaps, looking down at the actual sensors.
I washed the keycap assembly with water and a sponge, let everything dry, snapped the keyboard back into place, and presto! Good as new. the keyboard doesn’t feel crunchy anymore. Happiness ensued.
Oh, and you probably want to remove the battery before doing anything else.