Why is polishing ineffective for tree sap that has penetrated car paint?

[DiJaxon]

Tree sap that has penetrated car paint may not be removable by polishing if it has been left for too long. Here is some relevant information: Causes: Many plants secrete nectar or fruit juices that are corrosive. If these substances land on a car and are not cleaned promptly, they can easily damage the paint, leading to fading, discoloration, and loss of gloss, which affects the car's appearance. In severe cases, corrosion and blistering may occur. Typically, by the time tree sap is noticed, the stains have already dried and hardened, firmly adhering to the car body. Plain water is often insufficient to remove them, and the longer the delay, the more irreversible the damage becomes, eventually causing the paint surface to corrode, become pitted, rough, and lose its shine. Solutions: You can try using rubber clay to wipe off some small particles on the paint. Alternatively, soak a cleaning cloth in warm water and place it over the sap to melt it, making it easier to wipe clean. Additionally, specialized cleaning agents such as tar and asphalt removers or tree sap-specific cleaners can be used, as they are quite effective.