I doubt if the washer bottle is heated to prevent freezing but I guess you use anti-freeze to counter that - How about the mozzles though - Do they freeze up..?
Yes - Here in Finland we are using antifreeze liquid for washer fluid antifreezing and getting drunk. The story tells that bums are filtering this antifreeze stuff through a wheat bread to make the poisons dissappear. Unfortunately it does not seem to work. I am a member of a local volunteer firefighters and too often we are resuscitating these poor guys.
Few weeks ago I heard another method to filter this stuff drinkable: When there is -30 degrees Celcius outside, you just trickle this liquid along a crowbar. Story tells that all the poisonous ingredients freeze to the crowbar and pure alcohol is dropping from the other end. Maybe I should try this because at the moment there is quite a hard winter outside. Then I can offer you guys a drink at 3MA10!
By the way - I can buy a citron odeur antifreeze from here. If I'll try with this, I hope that the citron flavour is still there.
And back to topic:The nozzles are freezing but that is not a problem. Usually then the road is also icy and dirt is not flying like in wet conditions.