I unplug mine, turn it over and tap the bottom edge on the desk, then tap the top edge. Then I use an old toothbrush (clean, of course!) and run it between the keys, horizontally, then vertically, then blow it out with canned air and plug it back in and hope it still works! lol hmmm...looks like I need to do mine soon!
I'd read that you can run them under warm water and hang to dry, but have never tried it, nor would I recommend it, since it IS electronics.