Update:
Took the shield off the bike and removed all the hardware. Sat around one evening using duct tape on it. It worked but not as well as the first time. Maybe a good, hot day helps. After gettting all I could of the coating off the inside face, I attacked it with rubbing compound. I'd say the results are a 75% improvement. Good enough for now anyway.

I'll have to try the rain x product another time.