I have learnt something today as I went to 3M website and discovered “clear bra” for cars.
From what I read it is something you leave on, rather than using it as a winter cover they suggest you use it on vinerable areas. A clear version of the prited films used on buses and vans.
see
https://solutions.3m.com/wps/portal/3M/en_US/3M-Automotive/Aftermarket/Our-Brands/Scotchgard-Pro-Series/#WhereToUsePPF
I would still use a winter cover and clean the car when spring arrives, One would do that anyway
Frog