What would you guys suggest for de-icing a long rock drive. Have a buddy that has a house with a long, winding, steep rock drive that has a 50'-100' sharp drop off along the side of it. When we get 1" of ice or so they are pretty much stuck at home and do not want to chance his wife sliding off the hill. Snow is not that bad as he has a skid loader to plow with but when we get the ice that is his problem. How would you attack that if it was your problem? Liquid? Salt? thanks!