While were on this subject, I followed cayugad post on the 50/50 99% alc./windshield washer mix, all I had when I mixed it was RainX's winter grade (orange) that has the antifreeze agent in it as well as the window treatment. I didn't think of it when I made it but RainX puts a film on the glass that repels water. I haven't used the mix yet but I'm thinking it won't hurt, in fact it may help since it repels water. I just don't know about what if any residue it may leave behind. Any thoughts?