Tar spots from asphalt and adhesive residue from stickers or film bond extremely strongly to paint and glass. Mechanical removal without the right product means asking for scratches. A tar and adhesive remover dissolves the bond so you can wipe it away without applying force.

The principle is simple: solvents break the bond between the sticky substance and the paint. After dwelling you remove the residue with a soft cloth. Then clean the surface with an APC or IPA so no solvent residue remains before you apply wax or coating.