Well.......it's easy, but the "Mazda" is held on by posts! After you do this, you will have holes in your trunk!
(2 in the flying M's and 3 in the "mazda" badge).
Do a search on "debadge" before you try any of these things. There are a million and one threads on this.
is your friend!
Edited due to reponse by Rotr8