What is a safe pencil for marking auto primer paint?

A safe pencil for marking auto primer paint is a carpenter's pencil or a wax-based pencil, as these are designed to write on rough surfaces and are resistant to smudging. Avoid using standard graphite pencils, as they can leave marks that may not adhere well to the paint surface. Additionally, ensure that the pencil is non-toxic and suitable for use in automotive applications, as some materials may react negatively with paint. Always test on a small area first to ensure compatibility.