Right.....
I had a conservatory built last year.... and we left the plastic on all frames throughout the whole winter....
in spring .. i decided to take it off as all outside work was finished...
i used paint and varnish remover from B and Q.....
i tried it on a piece of spare upvc,,, it was fine...
so i put some on a cloth.... wiped it on an out of site frame..(gable side)
and the plastic melted off in 20 seconds...
so i then wiped it with a wet cloth... so it didnt continue to burn
left it until the morning... was fine...
so i did the rest in of the conservatory and it was all gone in 15 mins...
thats my own conservatory.....
So, its up to you if you want to do it on other peoples property...
but it works and its quick.