Showing yall how I am preparing my KBD Bumper (Rocket Bunny for 350z) for paint or wrap. Using ajax or bleach powder to create a mix, to remove the flexing agent on the bumper, You should remove the first coat with acetone and a rag. Them once its completely dry using flexible primer so that it sticks well and doesnt crack when flexing. Sand using 320 - 1000 grit sandpaper for nice surface to wrap or paint.

Paid Link: Primer (Recommend 2 so you don't have to order again)
https://amzn.to/3ykF3Ky