Summary: When detailing a car exterior, never use razor blades or any abrasive materials to remove tree sap. Remove tree sap effectively with tips from the owner of a car detail shop in this free video on exterior car details.
"Hi it's Dow here at the car wash, Firehouse car wash. And we are anxious to teach you how to get rid of tree sap, cause when you are detailing the exterior of a car, it's one of those annoying things that you don't sometimes even know what it is. It would be dark, look dark, maybe it even looks likes some bird poop on it. It gets on and it's sticky and gooey but with the hot sun baking it again and again, it turns into a usually a round type of just a blob on your paint. This is tree sap remover in a simple applicator purchased from our local supplier, Budco. Specialized product that we keep on our detail cart. So we have some we just simply cover that spot, let it soak, let it dwell and even sometimes agitate it just gently with my finger, no pressure. What you are basically trying to do is soften that tree sap, so that it can then be removed with a towel. Sometimes we'll see one or two spots if you park under a tree on a regular basis, then this doesn't have to be an evergreen, it doesn't have to be a, it can be a lot of trees with just weep, and they'll drop down you know tree sap and they'll leave on your car. It leaves you wondering what that was. It's simple to remove if you have the right products, there's no reason to attack it, don't use razor blades, don't use anything with abrasion in it. Just a tree sap remover, general cleaner should do a good job in getting it off."
eHow Article: Car Detailing: Tree Sap