Get a putty knife! I've used table knives before and its scuffed up the bottom. Although you can't see it, I still find it annoying as I know the marks are there.
One side will be easier to undo, the 2nd side will be a little harder as the innards will be squished against the metal housing as it'll be at a weird angle. Have patience, its easy to do.
When you're putting it back together, make sure that the ports are aligned with the case correctly. I've put mine back together before only to find that they're sticking out and no amount of pushing has got them back in again. You then have to go through the whole process of opening it up again. Do it slowly, make sure that everything is aligned before snapping it all back together again
pac