I was driving to work this morning and it was minus 5. My windscreen got completely covered in salt from the road and I couldn't see out. This accumulated over 20 minutes. I couldn't use my screen wash as it was frozen and I had to wait ages to find a place to pull over where I dumped a bottle of water on it. I've never known this in 30 years of driving. What can I do for driving home as it will be minus 3?