what can you use tree sap for
Applying mayonnaise to the area is also said to remove tree sap. Another technique is to use citrus-based solvents and children's molding clay. Apply a small amount of the solvent and rub with the clay. It is abrasive enough to scrub off the sap (which has been broken down by the solvent) without damaging the paint.
As tree sap flows through the sapwood part of the tree, it produces carbon dioxide. This creates positive pressure and if there are any wounds or holes in the sapwood, the sap will ooze out. This is how harvesting saps from trees is achieved; cut or create a hole.