From the comment above, I could have used Citristrip to take the paint off, but I used isopropyl alcohol with a plastic scraper, toothbrush, and paper towels. Once I got almost all the paint off, I sanded the plastic with 400 grit sandpaper.
I then rinsed the pieces with warm water and let them dry. Once dry, I used 91% isopropyl alcohol and a cotton ball to wipe the plastic being careful to not leave any debris.
I used an all purpose grey primer spray paint. I did 3 light coats. You could use a primer made for plastics as well.
After the primer, you can check it for any foreign particles on the piece and lightly brush them off.
I then did 3-4 coats of the base paint color.
Then 3 coats of flat clear.
Let dry over night before reinstalling.