If keys are getting stuck down, it sounds like lubing the keys might help. I've had decent luck with furniture polish, as it doesn't affect plastic or rubber, and is easy to apply in light doses. The Swiffer/Febreze stuff is fairly slippery, as I discovered when I cleaned some cabinets with it, and slipped on the laminate floor that had gotten some overspray. Other stuff is fine, too, though - it's all basically wax and oils in a can.
I just remove the top, flip it over, and spray lightly, aiming for the spaces between the keys. You can put something under the board to keep the keys depressed, to make sure the spray reaches the contact points.
Give it a few minutes to dry, and wipe any excess off. As a bonus, your board will smell better now, too. If keys are still sticking, you should be able to pull them and check for molding flash or imperfections, but the spray should help with the stiffness.
