Lexan is sold under many different hardness for different application, for airplanes and race cars I recommend using "Marguard" type Lexan
As far as a good cleaning fluids for all Lexan products (NOT Plexiglas ) I use to own and fly a small 190 MPH 4 place piston powered aircraft, one of the old timers at the local airport saw me buy a 1 gallon jug of "special", expensive spray window cleaner and told me that Pledge furniture polish was the same thing and a bunch cheaper, he was correct :shruggy
I use it, Pledge, on my airplane for 13 yrs. until it got total on the ground during a hail storm up here in Oregon and now that is all I use on my race cars with Lexan windows
Spray, liquid or any way you can buy it, they all work good for cleaning Lexan with a soft cloth like old cotton tee shirt, NOT paper towels