Just some things that we can say to YECs, “Look, if the earth really were six thousand years old, this is what we would expect to see. Do we?” Or something like that. And the usual general discussion around it.
Apart from the odd foray or two into discussions of omphalism, and the occasional YEC demanding that we reject the evidence of our eyes and our ears as their final, most essential command, the conversation has generally remained on track.