I also use alcohol. The higher the percentage, the better/faster it works.
If you get sap on the glass, the alcohol may leave a foggy mark on the glass. Just treat it as you would with the paint and hit it w/ a little wax, it will come right off.
2010 Torch Red GT Premium. 5speed, 19", security package, HID's, comfort package, 3.73, American Thunder Flowmasters.