My comment from the earlier thread;
Tell him to do what I did when my signs started being stolen. I bought some cheap gloves, and went to the nearest poison ivy patch. Rubbed the signs thoroughly with the ivy. Couple nights later, the signs were stolen again. The brat that lives next store, and his buddy down the street showed up with a bad case, all over their hands and arms. I said, “Joe! That’s a pretty bad case of poison ivy! Where’d ya get it?” He said he didn’t know. I went inside and laughed my butt off. Got some more signs, and “treated” them again!
LOL!
Poison Ivy - a great idea! And realistic.
You could probably just collect a bunch of the leaves, soak’em in alcohol or water, and make a solution, even a sprayable solution that you could spray on the signs or anything you didn’t want touched. In fact, now that I come to think about it, you could probably sell something like that, although someone would undoubtedly sue you for giving them poison ivy.