If you find the posts spam-like, at times off-topic, or consecutive, just report them with a proper reason and let the moderators take care of the rest. In the end most of the member's posts will be deleted, and two things could happen. He will either change his posting behavior or continue and start receiving bans.
It's quite difficult to delete his posts. They don't get deleted. I stopped reporting him

.
There are buffoons in every kingdom. There should probably be spammers on any forum who officially hold this position. Press the ignore button and let no one disturb your sleep.