Graffiti on historic structures poses a unique challenge, as it can devalue properties and mar their significance. Rapid removal is recommended to discourage further vandalism. Before removal, it's crucial to identify the graffiti type and the material it's applied to. Different building materials absorb graffiti differently, making its removal complex. Both chemical and physical methods can be employed, but it's essential to use the gentlest means possible. The National Center for Preservation Technology and Training (NCPTT) provides guidelines for preserving cultural materials and emphasizes the importance of careful planning, testing, and documentation before graffiti removal.