Pee on your headlight

So the other night I had just finished an install. I got in my truck and started to drive out of the floodlit site. As i got onto the road out, I noticed I couldn't see much. In fact I thought my headlights had not come on (they are automatic!) So I turned them on manually. Nothing. Hence I got out the truck and had a look.

Turns out that a day of driving on wet snowy roads had plastered the whole front thick with dirt. Totally. The dirt didn't simply wipe away either, which left me with a little problem. I needed to wash my headlights, but I had very little water and it was -10. The solution?
Simple, piss on them. Cleaned them up enough to drive with and got me safely to the hotel. Next morning while cleaning the windows at a petrol station I also wiped off the lights.