Dealing with annoying trade offers!

3 player keeper league. I have a guy that keeps sending me ridiculous bush league offers for CMC. Such as cmc and a 3rd for Kupp and slayton… his latest was trading for MT and offering me MT and Kupp for cmc and Moore… I’ve told him many times he would need to pay up if he had any chance for me to even consider trading cmc in a keeper right now. How do I get him to leave me alone, do I need to send him an absurd offer in return? These are our two teams

Send him back some absurd trade offer in response. He should get the message.