I travel for work alot, and just got home for the holidays. I found we have drain flies coming out of my wifes garden tub. I'm attempting to remove the drain stopper assembly so I can clean the drain out properly (lotsa hair keeping it from draining properly), and here's where you folks come in...

I unscrewed the top plug cap assembly, and found underneath it a brass piece which has a slot in the head maybe 3/4" diameter (assuming for removal) which is surrounded by a plastic tube which locks and unlocks the drain cap. How easy is the brass piece supposed to scew out? I haven't buggered up the slot in the head beyond use, but may get that way soon if I don't get some help.

Thanks in advance fellas!