Moisten a cotton ball or rag with rubbing alcohol. Clean the pen mark off the vinyl with the cotton ball or rag, and rinse the residue with a moist, clean rag.
Saturate a rag or cotton ball with a 3 percent solution of hydrogen peroxide. Set it on top of the pen mark, and let it sit for at least 30 minutes. The ink will transfer to the rag or cotton ball. Rinse well afterward.
Soak a cotton ball or rag with nail polish remover, and rub it on the ink to remove. Rinse afterward with a moist rag.
Moisten a rag or cotton ball with vinegar, and rub it on the ink. Then, rinse the vinyl with a moist, clean rag.