Cleaning a tub drain on a regular basis keeps clogs of hair and debris to a minimum. Drain plugs complicate this procedure if you don't know how to remove them, and each model has its own method of removal. Luckily all are simple, requiring few tools and only a few minutes.
Pull out the pop-up stopper in the drain, if that's the style you have. If the stopper pops up and down when you move a lever on the overflow plate -- the round metal plate below the tub spout -- you have a pop-up stopper. This should come out without the use of tools. The stopper is attached to a rod called a rocker arm, which will come out along with the stopper.
Unscrew the two screws in the overflow plate if you have a plunger-style stopper. The drain itself will be plain with no moving parts if you do.
Begin pulling the plate off. An entire assembly of metal links is going to come out along with it, so don't be alarmed. Pulling out the overflow plate and assembly is all you have to do for plunger-style stoppers because the stopper is in that assembly.
Turn the drain plug counterclockwise if the overflow plate doesn't have a lever. Plugs that you push and pull or turn to open and close should unscrew out of the drain.
Look for a small screw in the side of the plug's threads if the plug unscrews only part way. Loosen the screw partway and unscrew the plug all the way. You may have to take out the screw to release the plug.
Close flip-style plugs; these have a central disk that you push down on one side to open. Place a suction cup over the plug, press down and pull up once you have a good seal.
For all drains with overflow plate levers, set the lever so it is in the open-drain position. Removing the overflow plate is optional for pop-up stoppers, but because hair and scum can get into those metal links, you might want to pull this out anyway if you're cleaning. If the plug you're trying to unscrew in Section 2 still won't come out after removing the screw from the side of the threads, unscrew both the top cap and the insert you see underneath the cap. PlumbingSupply.com says this insert is a post that can sometimes become stuck in the drain.