Are there archaeological cases of graffiti that are not inscriptions on metallic surfaces eg plaques or personal adornment?

The oldest Graffiti I have seen was on a special shown on the Discovery Channel. They had Rabbi's, and Pastors discussing who Jesus Christ was. One Rabbi mentioned the parchments they have in storage which read "Here is the King of the Jews". Those parchments are considered "Graffiti" because they were temporarily posted by order of Temple leaders along the route Jesus Christ was going to be forced to walk. Unauthorized messages in public view is considered graffiti. The intent of graffiti is to inform.