-- Last Updated: Jan-08-13 9:03 PM EST --
then mayo or hand sanitizer. I have heard of peanut butter being used.
My trucks are in a pine grove. I have loads of sap on their tops. Alcohol per se does not work with large buildups. Try to get the worst off by mechanical means.
Razor blading this years accumulation is messy. Last years, which is dried, is much easier.