No, once plexiglass goes cloudy there is nothing you can do with it.
I have replaced some trailer windows
at our shop, its not a big job.
One thing when you replace it use Lexan or Marguard its the same
as plexi except it won't crack. Once replaced use a small amount of
Pledge furniture polish on a soft cotton rag and give it a good coat
this will help keep dirt and bugs from sticking and also helps hide
scratches. (this also works well for the Lexan headlight covers on