Last time I've used the stuff was about 3-4 years ago, long before I learned about autogeek. In any case, I believe this is what I used:
Clean, maintain and perfect them with 3M’s Plastic Polish. 3M Plastic Polish is step two of 3M’s plastic care system!
It's very easy to use, and left my brake lights and side markers looking new.
Btw, I applied by hand using a small pad and wiped it off with a rag. The days I would probably tape off the paint surrounding the plastic and apply with an applicator pad, and then wipe off with a microfiber or a towel and following up with some plexus. Good luck