I just used a small pocket flat blade that I had turned into a specialty tool for something years ago. The tip is bent at a 90 degree angle almost like a 90 seal pick but beefier. I just wedged it in where I could and kept pulling straight out all around the perimeter. I didn't rock it against the plastic. It didn't take much as I remember.
I only pulled them out because the one center rocket fell out, so the aim was to replace them.
Hutch