* Mascara is designed for use on eyelashes, so it is formulated to be safe for use near the eyes. Its ingredients include pigments (to provide color), oils, waxes, polymers (to provide structure and hold), and preservatives (to prevent bacterial growth).
* Shoe polish is designed for use on leather shoes. It typically contains solvents, waxes, dyes, and sometimes oils. These ingredients are not safe for use on the skin or near the eyes.
Using shoe polish as mascara could cause severe irritation, allergic reactions, or even damage to your eyes.