Our tubs have the kind of pop-ups that "Unscrew". I somehow removed one tub pop-up when trying to remove some hair and am afraid to replace it because I can not see any way to get turning tension on the inner brass post which spins freely inside the half-inch chrome tube. These are the simple push-pull type, not the pull and twist type which have a small finger on the side which fits in a slot on the chrome tube (that type I understand how to get turning pressure on the inner brass post) I can't figure out how to get screwing/unscrewing tension on the center brass post of ours. It is Watco patent #4720877. I looked at their patent on the .gov site and that didn't help me either. Please help. It should be a matter of pulling up whilst turning, or pushing down whilst turning, but neither way engages anything on the inner part.