Material we use for window glazing

[stewartingram]

Not sure if this is in the right section; not strictly model related but bear with me.

On another forum related to cars, I have suggested using Kleer on plastic rearlight lenses as a way of cleaning them up/making things clearer, somewhat in the way that we use Kleer when the internals of a coach window get fogged up with superglue fumes. This has now raised a reply as to what plastics we find in use as glazing material, as the sender has used some (unstated) product which have damaged plastic lenses. Any suggestions please?