I always just used a flathead screwdriver. I'd push the key down next to the one I'd want to remove, then just stick the flathead in and pop it up. Once 1 key comes off it's much easier to remove others... not to say that removing the first is hard, because it's easy.
Just be careful, if you start to feel something break/crack... stop. They key's are meant to come off, they should just pop right out, hell... you could probably pull off one of the F# keys with your bare hands.