During the spring and summer, you may find an unhappy surprise awaiting you if you park outside: sticky tree sap on your windshield. This tacky film can be very difficult to remove, even with ammonia-based and vinegar-based automotive glass cleaners that otherwise work very well.
The best way to remove this substance is a glass cleaner and one or two applications of rubbing alcohol (just the standard stuff in your medicine cabinet will do).
Apply the alcohol liberally to a clean, high-quality paper towel. Then rub the windshield and let it dry. If there is still a bit of cloudiness on the windshield, repeat the alcohol application a second time. Follow this with a liberal dose of glass cleaner and some new paper towels.
As with all cleaning jobs, it is best to avoid direct sunlight and to always try a small section first, just in case something unexpected happens.
For the inside of a windshield, try a cleaner specifically designed for auto windshields and clean paper towels. Two applications are usually all you need.
For newer vehicles: Before you spray the inside of a windshield, cover any sensors or apertures related to head-up displays and auto lighting and wipers. That will avoid damage from dripping cleaner. Also, keep your spray and your hands away from the auto-braking cameras in the area of the rearview mirror.
Source: Torque News