Like I mentioned earlier, some companies make tools for this sort of thing. For example, the Grind King skate tool (the one you need in order to maintain Grind King trucks) has a built in bearing removal nub on the end. However, it does the EXACT same thing as described here.
Remember, if you want to reuse your skateboard bearings and are unsure of your ability to remove them gently, by all means take your skateboard to a shop and ask for help! My first two times using this method, I destroyed my skate bearings in the process! Luckily, I make a habit of using cheaper bearings (Bones Reds), but still, I don't like to throw money away. The main point? Be gentle, take your time, and everything should be fine!
