i am a very open minded person, and welcome any good idea, screenwash is nothing new, and has been used by thousands of trad guys, and it is squeegeed of, hence no spotting, wfp is left to dry, remember that, i am 100% certain it does leave a film on the glass, it may get us by the freezing conditions, but i would not like to re first clean all over again after the thaw out, this is just my experience, but i could be wrong