Pine tree sap and needles

Spring brings blooming flowers, outdoor activities . . . and the arrival of tree sap. It can drip onto whatever is below, and that can often be your car. Left alone, tree sap can be unsightly at best. At worst, it can damage your car’s paint job and lead to rust.

We'll tell you the steps to take to remove the most stubborn sap—as well as bug residue and bird droppings—and prevent damage. But the most important thing to remember is that the longer you wait, the harder it will be to remove the residue.

“Get the sap off as soon as possible, because it will eventually eat through the paint, especially as the days warm up,” says John Ibbotson, chief mechanic at Consumer Reports’ Auto Test Center. “Heat accelerates how the sap sticks to the paint.” 

More on Car Maintenance

Tree sap is transported in tree veins and consists of nutrients, hormones, water, and sugars. “Sap will be visible on the surface or bark of a tree flowing from a wound, such as a saw cut or natural injury or disease,” says Michael Jascot, a maintenance specialist at CR’s test track who holds a degree in horticulture.

“Freezing nights and sunny days above 32 degrees promote the flow of sap after dormancy, although pine trees will ooze anytime of the year,” Jascot says. This is why sap starts flowing from a broken branch or cut in the tree during springtime.

Sap can damage your car because of how it bonds with the vehicle’s surface. Tree sap drops shrink over time, and as they shrink they create stress on your car’s finish because of that strong bond with the paint, says Dennis Taljan, a general manager at PPG, which produces car paints and other products. That tension can end up cracking a car’s finish.

Tree sap isn’t the only overhead threat; insects can be just as damaging. “There have been instances in which insects lay eggs on automobiles,” says Taljan. “When the sun arrives it scorches the eggs, and the decomposing material can etch certain automotive finishes.

“Bird droppings are another source of potential damage since they act similarly to the tree sap, shrinking and stressing the car’s finish,” he adds.

The finish on today’s cars holds up much better than paint jobs from 20 years ago. “Newer finishes are designed to resist a wide range of environmental assaults ranging from acid rain to abrasive dust,” Taljan says. “In addition, clearcoat formulations have been designed to have greater resistance to chemical attacks.”

What You Should Do

Cleaning tree sap off a car

Don’t let tree sap or bird droppings linger for days. You can prevent damage by safely removing those and other elements from your car's finish as soon as possible.

  • Start by thoroughly washing your car. “This removes any sediment and grime from the area you will be working in,” says Chris Jones, an automotive testing technician at CR’s Auto Test Center. “If the area around the sap is dirty, you’ll just be grinding the dirt into the paint as you try to remove the sap.”

  • Dab some rubbing alcohol on a cloth as your first line of attack. That may be all you need to get the job done.

  • If that doesn’t work, move on to a specialized tree-sap or bug-and-tar removal product, available at auto parts and hardware stores. “It’s best to test any cleaner or removal product out on a small spot of paint,” Ibbotson says. “That’s because it can damage the clearcoat and possibly the paint underneath.” If this happens, it will appear as discoloration of the paint or streaking. If the paint looks okay after testing, expand your work area.

  • Because these products can remove paint protectants along with the sap, be judicious in how much you use. Taljan says it’s important to use them in a shady area and in minimal amounts. "More elbow grease is better.”

  • It’s important to clean the area you worked on once the sap is removed. “Clean with soap and water immediately after removal of the tree sap or bird droppings," Taljan says. After that, you can apply a coat of wax to protect those areas.

Keeping your car waxed can help protect the paint over time. Our tests have shown that wax lasts only a few weeks, so it's best to wax at least once a season. And if you can, avoid parking near sap-producing trees, like pines, when possible.