The best method I have found is.....
600 grit --> 1000grit --> 2000 grit --> 3000 grit wet sanding, then buff it with a drill attachment and some plastic X until crystal clear.
All the sand paper, buffing attachment, and plastic X should cost you under 30 bucks.
I just did my sons Taurus with a turtle wax kit. It worked good and had the sealer included. I did use a wheel to buff it out. You could not see the unlit bulbs before and now its pretty clear
I think I will wax or something next time its around to hopefully buy some more time.