We always install the emblems with push-on nuts. If you can get a knife or small screwdriver under the edge, pry it up so that it "oilcans" away from the body. Do both sides and you can (yeah, riiiight!) grasp the nut along the short sides with pliers to remove it. If you're desperate, the nut is fairly brittle so squeezing both long edges together might snap it in half. Maybe.
