I wish I had the power of the cornfield here.
Back in the early 80's I was friends with Eddie Richardson, and this was about the same time that graffiti was starting to be sprayed on anything that was standing still in London. Someone decided to spray one of Eddies properties, and when they caught the miscreant he was discouraged by placing his hands on the curb and tapping them lightly with a sledgehammer until they made a squelching sound.
No more graffiti ever again, so this may also be a good remedy for hackers and such like.
I miss the old days and old ways.