First hand experience with their Plastx, it worked well but requires some effort. I put an old clean sheet on the carpet in the living room. Our top from the 7 zips out each window, so i could work on them separately. Some places had to be "cleaned" and buffed several times, especially the sides where it rubbed against the roll bar. Have fun, my arms were very sore, but it worked. [emoji1]
You need to use a plastic polishing compound. A couple come to mind. There is the "Mother's" headlight polish kit, and there is the https://www.amazon.com/NOVUS-7100-Plastic-Polish-Kit/dp/B002UCYRZU three part polish. The Mother's kit comes with everything. The Novus kit you will need a buffing wheel. You can use a drill to operate the buffer. You use a compound that varies in the amount of grit in it. Start course and work up to fine. It's like sanding anything, start course and work up to a fine grit. The drill and buffing wheel will save your arms and hands from exhaustion. 
