Sean's method will remove them in short order. When you remove the old tape, be careful as you can easily damage the emblem if you aren't careful, some type of solvent will help to remove the glued foam. Maybe carb cleaner, you don't need much. When you use new foam, just lay-on (stick-on) the foam double-sided tape (you leave the protective piece of removable material on, on one side until you do the next step) and then use an Xacto knife with a new blade to cut-out the excess around each letter, from the back. Again, be careful, because you could easily cut the plastic too, if you weren't watching your blade positioning.
Did you know that a piece of monofilament line will cut-through a piece of Schedule 40 PVC pipe? Make a couple of loops in a length of monofilament line, to put your fingers through, wrap it all-the way around the pipe, and use a back & forth motion, it works very well. Handy for cutting pipe in a narrow space like inside a wall cavity.