If I recall correctly and, assuming yours are attached like a later CL, I worked a bit of string underneath the edges/sides of the badge and pulled it towards the middle until it was right next to one of the pins (too far away from the pin, you're going to bend the badge), and slowly pulled up a bit to get some clearance. Do the same on the other side of the badge, next to the other pin. Then I think I just kind of lightly rocked/wiggled them while pulling away from the tank until they popped off.
The pins of the badge fit into a little sleeve/clip that, in turn, fits into holes on the side of the tank. Just friction fit. The clips are still easy to find.