Creating orange scratches/drawing on a C-print?

[bethanyb]

I've recently taken on a project where I need to write/draw on top of a c-print. I remember being able to create orange scratches (namely, drawing an orange mustache on a photo of my sister) on family photos when I was a kid, but I've forgotten the process involved. I've also tried an internet search on this process, but it's like I've gone crazy-- no one seems to have ever scratched their photos orange in the history of photography. Does anyone know how to do this?